delivered the opinion of the Court.
On September 28, 1968, Sergeant Frank Mazzone, a Maryland State Police officer working under cover, was advised by other police officers that Michael Isele, a police informer, had informed them that he had been invited by the appellant Regie to participate in a robbery. Mazzone immediately contacted Isele, whom he previously knew, and together they went to see the appellant. Isele introduced Mazzone to the appellant as a prospective participant in the planned robbery. After some dis *349 cussion, the appellant invited Mazzone to participate in the robbery. While appellant did not then specify the place to be robbed, he indicated to Mazzone that Richard Fields had been involved with him in planning the robbery, and that he would also participate in the crime. Appellant, Mazzone, and Isele then met with Fields and the robbery plan was outlined by appellant and Fields. The need for guns was discussed and appellant and Fields spoke of the necessity of killing two employees at O’Donnell’s restaurant, the situs of the proposed robbery. The four men then drove in Isele’s car to appellant’s home where appellant phoned Kent Chamblee for the purpose of purchasing a shotgun. Thereafter, the men drove tо Chamblee’s home, purchased the gun from him, and tested it in his presence. While Chamblee knew that the shotgun was to be used “for a job,” he did not accompany the others when they then drove to the restaurant to perpetrate the robbery. Upon arriving there, Mazzone told appellant that he first wanted to “case” the restaurant. This being agreed, Mazzone and Isele went into the restaurant while appellant and Fields went to a nеarby bar to await their return. Once inside the restaurant, Mazzone contacted police headquarters and requested assistance. Thereafter, he and Isele left the restaurant and rejoined appellant and Fields. While several police cars promptly responded to the scene, Mazzone found it necessary, in the interim, to reveal his identity as a police officer and to arrest appellant and Fiеlds at gunpoint. At the same time he also arrested Isele in order “to cover him.” After the arrest, appellant made an incriminating statement to the effect that he and Fields had planned the robbery and that he had invited Isele to participate in the crime.
Appellant, Fields, and Chamblee were thereafter jointly indicted for conspiracy to rob with a dangerous and deadly weapon and for carrying a deadly weapоn openly with intent to injure. Appellant was separately tried by a jury, found guilty on both counts, and sentenced to twenty years on the conspiracy charge, and two years, concurrent, on the weapons offense.
*350 The docket entries indicate that the conspiracy indictment against Chamblee was nol prossed prior to appellant’s trial. It also appears that at his trial appellant established through the testimony of a poliсe officer that Fields had been examined by State psychiatrists at the Clifton Perkins State Hospital and found “not guilty by reason of being insane at the time of the alleged crime.” The State did not rebut the officer’s testimony, although the record indicates that two of the State psychiatrists who had examined Fields were then present in court.
Against this background, appellant contends that since the indictment against Chamblee was nol prossed, only he and Fields were charged as conspirators; and that because Fields was found insane at the time of the commission of the crime and thus was not a person legally capable of engaging in a criminal conspiracy, his own conviction cannot stand since one person alone cannot be guilty of the crime of conspiracy.
Conspiracy — a common law misdemeanor in Maryland — is defined as a combination by two or more persons to accomplish a criminal or unlawful act, or to do a lawful act by criminal or unlawful- means.
Jones v. State,
As one person cannot conspire or form a combination with himself, it is essential in proving the existence of a criminal conspiracy to show “the consent of two or more minds,”
Bloomer v. State,
In view of these principles, it is the well settled general rule that one defendant in a prosecution for conspiracy cannot be convicted where all of his alleged co-conspirators, be they one or more, have been acquitted or discharged under circumstances that amount to an acquittal. Hocheimer on Criminal Law (Second Edition) Section 290; Clark and Marshall, Section 9.07; Wharton’s, Section 91; Perkins, p. 533. The validity of the general rule has been consistently recognized by the Court of Appeals.
See State v. Buchanan,
5 H & J 317;
Bloomer v. State, supra; Hurwitz v. State,
Generally speaking, it would appear that so long as the disposition of the case against a co-conspirator does not remove the basis for the charge of conspiracy, a single defendant may be prosecuted and convicted of the offense, even though for one reason or another his co-conspirator is either not tried or not convicted. See the exhaustive collection of casеs at
Some cases suggest that the rule that acquittal of all savе one of the alleged conspirators results in the acquittal of all applies only to acquittals on the merits.
See Farnsworth v. Zerhst, supra.
Other cases — while recognizing that acquittals are not always tantamount to a declaration of innocence — nevertheless conclude that an acquittal is in effect a judicial determination, binding on the State, that the acquitted defendant was not a participant in a criminal conspiracy.
See United States v. Fox,
“* * * the insanity [of appellant’s brother] would not exculpate the appellant if he conspired with the principal or aided or abetted *354 him in the killing of the deceased * * *. If appellant so conspired оr aided or abetted in the homicide, the mental irresponsibility of [his brother] could not be invoked to exonerate said appellant. One may or could use an insane person as the agent of destruction — or conspire with such person to accomplish the homicide — just as guiltily as with a person of sound mind. The fact, if true, that the co-conspirator or principal in the crime is not amenable to justice because of mental irresponsibility does not exempt the other from prosecution. Pruitt v. State, 91 Tex. Cr.R. 189,237 S. W. 572 ; People v. Armstrong,299 Ill. 349 ,132 N. E. 547 ; Conley v. People,170 Ill. 587 ,48 N. E. 911 ; 22 C.J.S. Criminal Law, §§ 85,101.”
We think the cases relied upon by the
Jones
court to support its conclusion stand for the proposition that it is no defense to one who participates either as a principal or aider or abettor in the actual commission of the substantive criminal offense that the principal offender was insane at the time of the crime. The principle would appear similar to the rule that а co-conspirator may be convicted of any crime committed by any member of a conspiracy to do an illegal act if the act is done in furtherance of the purpose of the conspiracy. The conspiracy being established, the fact that the member who committed the crime was insane at the time would thus not exonerate the others from complicity in the commission of the substantive offense.
See State v. Alton,
We do not find thеse cases controlling of the primary question before us, namely, whether
under an indictment for conspiracy,
one conspirator may be convicted of the offense where the only other conspirator was shown to be insane at the time the agreement between them was concluded. Conspiracy to commit a crime is a different offense from the crime that is the object of the conspiracy. One necessarily involves joint action; the other does
*355
not. By its nature, conspiracy is a joint or group offense requiring a concert of free wills, and the union of the minds of at least two persons is a prerequisite to the commission of the offense. The essence of conspiracy is, therefore, a mental confederation involving at least two persons ; the crime is indivisible in the sense that it requires more than one guilty person; and where the joint intent does not exist, the basis of the сharge of conspiracy is necessarily swept away.
See Feder v. United States,
The evidence in the record before us plainly shows that appellant and Fields planned to commit a robbery at O’Donnell’s restaurant. There is some evidence in the record to suggest that Chamblee may also have been a conspirator, although the State made little effort at the trial to establish his involvement in the conspiracy. Since an insane person is mentally incapable of forming a criminal intent,
Bradford v. State,
As to Chamblee, the docket entries indicate the entry of a nolle prosequi to his conspiracy indictment. We cannot ascertain, therefore, whether, in the circumstances in which it was entered, the nolle prosequi operated as an acquittal or not. See Greathouse v. State, supra. It appears, however, from colloquy between counsel and with the court that Chаmblee was permitted to plead to a lesser offense than conspiracy, possibly with the understanding that he would not thereafter be charged with that offense.
In his advisory instructions to the jury, the trial judge, after fully defining the crime of conspiracy, stated that under Maryland law where only two parties are involved in the alleged conspiracy, and one is found not guilty, “the other could not be tried because one person cannot cоnspire except with another to commit a crime.” He further advised the jury that there has to be “an outright finding of not guilty” but such was not the ease with Fields who was merely found to be insane and for that reason not brought to trial. With reference to Chamblee, the trial judge instructed that he had not been found not guilty of conspiracy; that he did not believe that Chamblee had been prosecuted for that offense.
While appellant made no objection to the court’s instructions, on the state of the record before us we think they constituted “plain error * * * material to the rights of the accused” under Maryland Rule 756 g.
See Parker
*357
v. State,
We also find plain error material to the rights of the accused in the court’s instructions to the jury concеrning the offense of carrying a deadly weapon openly with intent to injure. The court instructed the jury that the testimony showed that appellant carried the weapon “out on the street and wigwagged [it] at several people who went by” and that if they believed this testimony it would support a conviction. The record discloses that this incident occurred at 14th Street and Wallace Place in the District of Columbia, and not in Maryland. If this were thе only evidence adduced at the trial to support a conviction for this offense, it is apparent that it would have been legally insufficient, there being no jurisdiction in Maryland courts to try offenses committed in the District of Columbia.
See Frasher v. State,
*358
In view of our disposition of the case, we need not consider other questions raised by appellant, with one exception. By pretrial motion appellant indicated his intention to defend against the conspiracy charge on the theory that he had been entrapped by Isele, a police agent, into committing the offense. That the defense of entrapment is applicable in conspiracy casеs is settled.
Hummelshime v. State,
The record discloses, however, that the prosecutor filed two petitions for writs of Habeas Corpus Ad Testificandum, alleging in the first petition that Isele was. a federal prisoner detained in the penitentiary at Lewisburg, Pennsylvania, and, in the second petition, that he was incarcerated at the federal penitentiary in Danbury, Connecticut. In each petition, the State alleged that Isele was a material witness in appellant’s case and sought to secure his attendance at the trial. We must assume that Isele’s presence was not secured because, at the trial, the prosecutor expressed a lack of • information concerning Isele, including, as we read the record, Isele’s present whereabouts. In any event, the court denied appellant’s motion, renewed at the trial, that the indictment be dismissed for failure of the State to reveal Isele’s address. .
Since appellant already knew Isele’s identity, this is obviously not a case involving disclosure of thé
identity
of an informer whose testimony was necessary and relévant to a fair defense.
See Nutter v.
State, 8 Md. App.
*359
635;
Whittington v. State,
Judgments reversed; case remanded for a new trial.
Notes
. By the Maryland stet procedure, the prosecutor indicates that he does not choose at that time to further prosecute the indictment.
. This would not be true, however, if after elimination of the alleged entrapper, there are at least two other parties to the conspiracy.
. We do not here either adopt or reject the holding in this case.
