I'm pretty sure they did as well. What else was kept was Jareds evidence that was routinely tested until touch DNA technology caught up with it 2 years ago.
Here is an excerpt from
Finding Jacob Wetterling, with key points in boldface, that address the question about the tires being returned, among other key issues....
The FBI interviewed Heinrich again on January 12, 1990. He was wearing a pair of tennis shoes during the interview and admitted to investigators that it was the only pair of tennis shoes he owned and that he had purchased them at Sears about a year before. He gave his shoes to the investigators so they could perform tests on them.
Three days later, on January 15, 1990, Heinrich surrendered the rear tires on his blue 1982 Ford EXP. He told the investigators he had purchased the Ford EXP in September 1989, a month before the abduction.
On January 15, 1989 Detective Pearce obtained documents that indicated Heinrich had purchased the 1987 Mercury Topaz on March 10, 1988. The car had been repossessed on March 15, 1989.
Detective Pearce was able to track down and contact the people who had bought the 1987 Mer-cury. The new owners of the car voluntarily drove it to the Stearns County Sheriff's office on January 16, 1990. Pearce brought Jared into the Sheriff's office to view the vehicle. Jared sat inside the Topaz for a few minutes and agreed that the car "felt like" the car he had been kidnapped in, and he said he "wouldn't change a thing about the car's interior." When asked to rate the Topaz on a scale of 1 to 10, with a 10 being the most similar to the car he was taken in, he rated it as an "8" or a "9".
Detective Pearce collected back seat and carpet fiber samples from the Mercury Topaz formerly owned by Heinrich on January 18, 1990. The samples were retained for testing against fibers from the clothing Jared wore during the January 13, 1989 assault.
On January 24, 1990 investigators executed a search warrant on the home owned by Howard Heinrich, located at 16021 County Road 124, east of Paynesville. Danny's younger brother, Tommy, had told investigators that Danny had been living in the basement of his father's house since November 30, 1989. Officials seized a number of items from Heinrich's home including a black portable police scanner carrying case, lists of police scanner frequencies and user manuals, a pair of black lace-up boots, two brown caps, a Radio Shack scanner frequency book, and a pay stub from Fingerhut dated October 8, 1989. They also confiscated a brown vest, a Regency programmable handheld scanner, and a six-channel Regency scanner.
It is interesting to note that January 24, 1990, the day the search warrant was executed at the Heinrich home, was also the same date that Duane Allen Hart was arrested and charged with several counts of sexually assaulting juvenile boys.
FBI agents returned to the Heinrich home the next day, January 25, 1990. This time, Danny's father, Howard, was also present. Danny agreed to come to the Stearns County Sheriff's office the next day to pick up the rear tires that had been removed from his 1982 Ford EXP ten days earlier. Heinrich arrived at the Sheriff's office on January 26, 1990 and agreed to participate with five other white males in a physical lineup for Jared to view.
When Jared viewed the lineup, more than a year had passed since he had been kidnapped and assaulted, and he was unable to positively identify any of the men as being the man who had assaulted him. He did identify Heinrich and one other person as being similar to his kidnapper, but he rated Danny as just a “4” on a scale of 1 to 10, and the other man was rated a “7.” Photographs of Heinrich demonstrate that his physical appearance fluctuated significantly, even over relatively brief periods of time. It is unknown how significantly Heinrich’s appearance changed in the year that passed between the date of Jared’s assault and his viewing of the lineup.
On January 26, 1990 the FBI Laboratory called Wetterling investigators and told them that the tires from Heinrich's 1987 Mercury Topaz were consistent with tire impressions that were left at the scene of Jacob Wetterling's abduction. The consistencies were specific to the tread design and size of Heinrich's Sears Superguard tires. However, the tires could not be considered a perfect match because there were no distinguishing characteristics or defects in either the tires or the tread marks in the sandy gravel driveway to provide enough evidence to call them a match.
The January 30, 1990 issue of the Paynesville Press carried a front-page article about the arrest of Duane Allen Hart. The article again referenced the ongoing investigation of the assaults of the young boys in Paynesville.
That issue marked the fifth time that the Paynesville Press had published an article about the assaults or attempted kidnappings of young boys in town.
FBI investigators arrested Danny Heinrich for probable cause for the kidnapping and assault of Jared, on February 9, 1990, more than a year after the January 1989 incident. The consistency between the fibers found in Heinrich's car, and on the snow pants that Jared wore the night of his assault, was the basis for the arrest. As described in Al Garber's book, Striving To Be The Best, the interview room was staged with furniture, special lights, and a flag. Heinrich told the investigators that he was not guilty of Jared’s assault and that he was being framed. Heinrich demanded an attorney and refused to speak to investigators any further. He was subsequently released without being charged.
Of significant interest with regard to Heinrich's 1990 arrest was the apparent dissent between investigating agencies. The FBI moved forward with the arrest without consulting with the BCA and against advice from the Stearns County Attorney’s office. Garber notes that the Stearns County district attorney was furious that Heinrich had been arrested prematurely.
One day short of the anniversary of Danny Heinrich's arrest, on February 8, 1991, investigators returned to Heinrich all of the property that had been seized during the January 24, 1990 execution of the search warrant on his father's home.
On April 2, 1991, Paynesville police officer Stephen Lehmkuhl requested assistance from the Stearns County Sheriff’s Department. City residents had complained about a strange man driving a tan-colored vehicle that had been witnessed following boys on their newspaper delivery routes. A Stearns County deputy was dispatched to perform surveillance and he observed a tan-colored 1984 Buick driven by Danny Heinrich. Heinrich appeared to be following a paperboy through the down-town area. The deputy noted that although it appeared that Heinrich was stalking newspaper boys, that he did not have probable cause to pull him over. The deputy wrote a report but no further action was taken.