The defendant Doyle was tried on eleven indictments charging him with “procuring the burning of a building in the town of Holliston.” A jury found him guilty on eight of the eleven indictments and he was sentenced. He brings this appeal pursuant to G. L. c. 278, §§ 33A-33G. The Commonwealth’s chief witness on ten of the eleven indictments was William Canavan, a teenage neighbor of the defendant. Canavan had been acquainted with Doyle for approximately a year before the first of the fires involvеd here. During that time they went bowling together regularly and participated together in other activities. Canavan frequently accompanied Doyle in chasing fires locally and in Boston and went with him to the SPARKS Club 1 headquarters. Dоyle drove a red car with five radio scanners in it for monitoring fire and police calls and had additional scanners in his home. He also had a part-time job as a fire insurance adjuster.
Most of Canavan’s testimony invоlved the circumstances of eleven fires in the Holliston area which occurred at various intervals between April, 1973, and September, 1974. Canavan testified that the first fire took place after he and three of his friеnds, Mark Bomchak, Billy Boston and Michael Potter had been at James Doyle’s house on April 17, 1973. Doyle remarked to them: “It’s a little dull around here, why doesn’t somebody go out and do something exciting like light a fire.” Potter and Boston аgreed to start one and Doyle showed them how to light it. After the fire had been started, they all drove around for a while in Doyle’s car to avoid suspicion and returned to the scene of the fire to watch it after it had bеen reported over the *546 radio. Later testimony of Boston and Bomchak substantiated the details of this incident.
Canavan testified that the other ten fires were lighted by him after conversations with Doyle in which the defendant suggеsted that Canavan should light a fire to alleviate the lack of excitement. Doyle either proposed a site or asked Canavan to do so. He would then discuss with the teenager how the fire was to be lighted. Sometime after January, 1974, Canavan started lighting the fires with Dura Flame logs which Doyle provided. When the alarms for the fires came over the scanner radios, Doyle and Canavan watched the buildings bum.
Gregg Spiller, another teenаge neighbor of Doyle, who was sixteen at the time of trial, told the jury of a conversation he had had with Doyle in approximately April, 1973, in which Doyle asked Spiller if he would light a fire in a tree house for which action Spiller would be paid ten dollars. Spiller declined.
The fire chief of Holliston testified for the Commonwealth concerning the details of the fires alleged in the indictments. He had investigated all of them and had confirmed the loсations and dates specified by Canavan. He found traces of Dura Flame type logs at three of the fires. However, a number of the buildings had burned completely. In these instances there remained no evidencе of the cause of the fires which were then reported as of “undetermined” origin.
The defendant presented several witnesses to impeach the testimony of Canavan; but they furnished no substantial contradiction of his tеstimony. Two of the defendant’s witnesses testified that Canavan did not have a good reputation for truth and veracity in the community. The defendant’s appeal raises four issues.
1. The defendant claims that his motion to sever triаl on one of the eleven indictments from the remaining ten was erroneously denied. This indictment, No. 114,197, charged the defendant with procuring Boston to set a fire on April 17, 1973. The other ten indictments dealt with fires set by Canavan beginning in August, 1973, and extending for a *547 period of about a year. The defendant contends that the April 17 fire was distinct from the others “in principals, victims, time, and proof” and that severance was required.
Whether or not indictments joined for triаl should be severed is a matter within the sound discretion of the judge.
Commonwealth
v.
Iannello,
2. As already related, Boston and Bomchak testified to the details of the fire which occurred on April 17,1973, and Spiller testified to an occasion on which the defendant solicited him to set fire to a tree house. The defendant con *548 tends that the admission of the testimony of these thrеe witnesses was error because it was evidence of other crimes introduced to prove the crime charged and was insufficiently related in time, plot and design to the acts for which the defendant was on trial.
This argument is based in some measure on the defendant’s assumption that indictment No. 114,197 should have been severed from the others, and that therefore there was no justification for the admission of testimony in support of that indictment. Since we have decided that the indictment was properly joined with the others, the testimony was admissible to prove the offense charged in that indictment. Even if it were not the subject of a properly tried indictment, thе challenged testimony of Boston and Bomchak as well as that of Spiller was admissible.
The general rule governing the admissibility of evidence of similar criminal acts was stated by this court in
Commonwealth
v.
Deschamps,
3. Prior to Canavan’s testifying before the grand jury, an assistant district attorney gave him a paper purporting to be a grant of immunity from prosecution in exchange
*549
for his testimony. Beforе trial, the judge determined that the decision in the recent case of
Grand Jurors for Middle-sex County for the Year 1974
v.
Wallace,
The record makes clear that the judge carefully and precisely informed Canavan that the purported grant of immunity was invalid, that the reprеsentations made by the assistant district attorney were not binding on the Commonwealth, and that Canavan could be prosecuted if he chose to testify. Where an unindicted accomplice voluntarily waives the Fifth Amendment privilege without a grant of immunity, no corroboration of his testimony is required under Massachusetts law.
Commonwealth
v.
Taber,
*550
Even if it were assumed that Canavan could properly be regarded as an immunized witness, G. L. c. 233, § 201, requires only that there be “some evidence in support of the testimony of an immunized witness on at least one element of proof essential to convict the defendant.”
Commonwealth
v.
DeBrosky, supra,
at 730.
Commonwealth
v.
Turner,
4. The defendant’s final claim of error concerns testimony sought to be introduced through his wife to impeach the credibility of Canavan. In the course of his direct testimony Canavan stated without objection that during a conversation he had with the defendant, the latter said that he might divorce his wife. The evidence which the dеfendant later sought to introduce through Mrs. Doyle was that she and the defendant had recently renewed their marriage vows on two separate occasions. Whether the defendant was planning to obtain a divorce was clearly collateral to the issue which was the subject matter of the trial. While testimony bearing upon collateral issues may be introduced in the discretion of the judge (see
Commonwealth
v.
Hersey,
Judgments affirmed.
Notes
The SPARKS Club, as described by its president at trial, is an organization of firemen and civilians whose purpose is to aid metropolitan fire departments in emergencies and to promote friendly relations and better understanding between civilians and professional firefighters.
The applicable stаtute is G. L. c. 233, § 20I, inserted by St. 1970, c. 408, which provides: “No defendant in any criminal proceedings shall be convicted solely on the testimony of, or the evidence produced by, a person granted immunity under the provisions of section twenty E.”
