Duаne Carter Olson was charged in a two-count indictment with manufacturing in excess of fifty marijuana plants in violation of 21 U.S.C. § 841(a)(1), and using a firearm in relation to a drug trafficking crime in violation of 18 U.S.C. § 924(e). Olson filed a motion to supрress evidence seized during a search of his property. The district court denied his motion. He subsequently pleaded guilty to the firearms count, 1 and was sentenced to sixty months in prison. Pursuant to the plea agreement, Olson reserved the right to appeal the district court’s denial of his suppression motion. We affirm, finding that there was probable cause to support the issuance of the search warrant.
I.
In late 1992, local drug task force agents received a tip from an apparently unknown informant that Olson was cultivating marijuana in a mobile home on a farm where he was living and that he owned various weapons. That information was corroborated a few months later by an informant believed to be reliable who reported similar activity. 2 Based on the information, the agents undertook an independent investigation of Olson and his prоperty.
The agents took aerial photographs of the property and confirmed that there was a mobile home on the site and that the farm did not appear to be operational. Using a Fоrward Looking Infrared (FLIR) device 3 mounted to a state patrol helicopter, the agents were able to observe a significant amount of heat coming from within the mobile home. 4 The results of the device were simultaneously recorded on videotape. 5 Several other neighboring farm sites were scanned using the FLIR. These sites did not exhibit the same elevated temperature as the mobile home on Olson’s proрerty. In addition to the heat emissions, the agents observed what appeared to be a venting system on the roof of the mobile home.
The agents subpoenaed Olson’s electrical records for the previous few years and, for *849 the purpose of comparison, the records of the prior tenant. The records revealed that 01-son’s average electrical usage was markedly high — three to four timеs that of the prior tenant. Managers of two local electric cooperatives found Olson’s power usage to be “[s]omething non-weather related with a constant draw” and “high for a single person with no apparent agricultural operation.” Affidavit at 5. Agent Scott Steffes of the drug task force noted that Olson’s high electrical usage was consistent with the power usage commonly associated with indoоr marijuana growing operations. Id.
The above information was included in an affidavit, and based on this information, a search warrant for Olson’s property was issued. The search of Olson’s mobile home uncoverеd an indoor marijuana growing and processing operation. In addition to marijuana plants and various items used to grow marijuana (e.g., grow lights, electric timers, heaters), firearms and ammunition were recovered.
II.
Olson advances two arguments on appeal: First, he argues that the use of the FLIR imaging device absent a search warrant was a violation of his constitutional rights under the Fourth Amendment; second, he argues that the affidavit in support of the search warrant was fatally defective because it did not contain the basis of knowledge for the informants’ information. We find that there was sufficient evidence, independent of the information obtained through the use of the FLIR device, to support a finding of probable cause. Therefore, we do not, and indeed need not, address the issue of whether the use of the FLIR device was a violаtion of Olson’s Fourth Amendment rights, for even if we were to find such a violation, “[ejvidence ... obtained from sources other than the infrared inspection is not ‘fruit of the poisonous tree’ and its exclusion is not warranted.”
6
United States v. Kerr,
Under the “totality of the circumstances” test enunciated in
Illinois v. Gates,
the task of the reviewing court is “simply to make a practical, commonsense decision whether, given all the circumstances set forth in the affidavit ... including the ‘veracity’ and ‘basis of knowledge’ of persons supplying hearsay information, there is a fair probability that contraband or evidence of a crime will be found in a particular place.”
The magistrate who reviewed Olson’s suppression motion found that there was in fact no basis of knowledge fоr the informants’ information, but nonetheless held that the *850 agents’ corroboration of the information supported a finding of probable cause. See Magistrate’s Rpt. and Rec. at 6. We agree that the independent investigation by the drug task force agents in this casé was adequate to support a finding of probable cause.
The agents verified that there was a mobile home on the farm site where Olson was purportedly living, and- that there was no visible agricultural activity or livestock. They also learned that there was what appeared to be a venting system in the roof of the mobile home (apparently used to vent excessive heat). Finally, and perhaps most importantly, they obtained Olson’s electric records which showed that Olson’s electrical usage was abnormally high (three to four times higher than that of the prior owner). All of these facts, although individually consistent with innocence, taken together support a finding of probable cause. The informants’ reliability was further established by the proven track record of one of the two infоrmants, who had provided information in the past that led to numerous drug convictions. Affidavit at 3.
We hold, therefore, that notwithstanding the lack of a basis of knowledge for the informants’ information, the search warrant was nоt fatally defective, because there was sufficient, other evidence from which a finding of probable cause could be made. Our holding is supported by the teachings of both the Supreme Court and this court. In
Gates,
thе Supreme Court explained that an informant’s reliability and basis of knowledge “are better understood as relevant considerations in the totality-of-the-circumstances analysis that traditionally has guided probable-cause determinations: a deficiency in one may be compensated for, in determining the overall reliability of a tip, by a strong showing as to the other, or by some other indicia of reliability.”
7
We find, in sum, that the district court properly denied Olson’s motion to suppress the evidence obtained during the search of his property.
Notes
. The marijuana count was dismissed pursuant to the plea agreement.
. It is not entirely clear from the affidavit supporting the search warrant of Olson’s property whether there were two informants or just one. The gоvernment maintains that there were two informants. Although the affidavit is ambiguous in this respect, we agree that it can reasonably be read to support the inference that there were in fact two informants.
. The FLIR dеvice is a passive, nonintrusive system that detects differences in temperature of the surface of an object being observed. The device does not send any beams or rays into an area on which it is fixed, nor does it penetrate structures. Affidavit at 4. A type of thermal imaging device was apparently first developed by the United States Army to locate enemy vehicles in combat operations. Thermal imaging devices have since had other applications (e.g., geological research, detecting overloaded power lines), and are increasingly being used by police to detect indoor marijuаna growing operations.
. An area of bright white was readily apparent and visible on a portion of the roof of the mobile home.
. Still photographs of the mobile home were made from the videotape. The photographs revealed rafters on the north side of the mobile home that were visible due to the extreme heat. The agent who reviewed the videotape noted as well that the mobile home appeared to be split into two rooms; the divider wall was visible due to the transfer of heat from the north end of the home into the wall.
. There is a split of authority on whether the use of a thermal imaging dеvice constitutes a "search" within the meaning of the Fourth Amendment. District courts in both the Ninth and Third Circuits have held that the use of such a device is not a “search."
See United States v. Kyllo,
. The Court noted, for example, that
if a particular informant is known for the unusual reliability of his predictions of certain -types of criminal activities in a locality, his failure, in a particular case to thoroughly set forth the basis of his knowledge surely should not serve as an absolute bar to a finding of probable cause on his tip.
