"I have reason to believe I may have been provided inaccurate documentation and recommendation in evaluating the permit application," Thomson wrote in a letter to Prosecutor Warren W. Faulk dated Sept. 7.
"As a result of this situation, it is evident to me that the motivation was to cause harm to the applicant and as well to myself," he said.
The letter was written days after The Inquirer reported that Thomson had signed off on the permits for Jenkins.
According to sources, the state police had launched a probe into how Jenkins got the permits after a Camden officer told them Thomson was made aware of the councilman's record when he approved the permits on July 8.
State police confirmed this month that they had begun an inquiry.
Thomson, who was in Toronto at a conference of police chiefs, would not comment on the letter Tuesday.
In addition to investigating "the sources of the documentation that was relied upon in approving [Jenkins'] application," Thomson's letter called upon the Prosecutor's Office to look into how details of the councilman's gun-permit application became public.
Thomson said the leak was an apparent violation of state confidentiality rules surrounding firearms applications and background checks.
"This jeopardizes the integrity of the entire process by denying applicants of a thorough and impartial investigation," he wrote. "It can also create a character assassination of an individual based on rumors, half-truths, and lies."
A spokesman for the Prosecutor's Office said Tuesday that he could neither confirm nor deny the existence of the letter to Faulk or an investigation.
A Camden County official confirmed the letter's authenticity.
Under state law, Thomson has sole responsibility for approving gun permits for qualified Camden residents. Background checks are performed by members of the Police Department, and the results are given to him to review.
The Prosecutor's Office is in possession of the original documents on which Thompson based his approval, he wrote in the letter.
Jenkins agreed on Aug. 25 to surrender the permits, which authorities said had been issued because of an administrative error.
The councilman said he was told by the Prosecutor's Office that he should have disclosed his fraud conviction on the May 19 application. He said he was unaware that he was required to report a conviction for a nonviolent offense.
A source familiar with the application said a background check, dated July 1, was run through the National Crime Information Center. It showed Jenkins' guilty plea and that he received a sentence of four years' probation, the source said.
Contact staff writer Darran Simon at 856-779-3829, firstname.lastname@example.org, or on Twitter @darransimon.