Tempe, Ariz. -- An undercover Arizona police officer has resigned and is under investigation following allegations that she had an affair with a suspected drug dealer whom she was investigating, allegedly jeopardizing the months-long investigation and blowing the cover of fellow officers.
Former Tempe Police Department Det. Jessica Dever-Jakusz began an investigation into the sale of illegal drugs on Mill Avenue in Tempe, Ariz., in June, according to a police report. Dever-Jakusz, who is married to a cop, was assisting in the initial stages of the investigation because of her "tenure and prior experience as a narcotics detective," the report said.
The detectives were provided with the drug MDMA, more commonly known as Molly, from an alleged drug dealer whose name has been redacted from the police report as part of the undercover operation.
The police report alleges that Dever-Jakusz "began engaging in a romantic relationship" with the suspect around Aug. 1, 2013 and that the relationship was sexual in nature.
Dever-Jakusz "did not initially disclose her profession or affiliation with the Tempe Police Department" to the suspect, but, in October, allegedly told him about the ongoing drug investigation and that the people with her during the previous drug transactions were also undercover detectives, the report states.
Dever-Jakusz has not responded to ABC News' request for comment. The Maricopa County Attorney's Office did not know whether she has retained an attorney.
According to the police report, an anonymous source tipped police off to Dever-Jakusz's relationship with the alleged drug dealer.
The suspected drug dealer came to the police department to tell them about the affair with Dever-Jakusz and the information she had told him about the investigation. He also said he knew that the detective's husband was a police officer in a different department, according to the report.
The suspected dealer showed police text messages "of an explicit sexual nature" exchanged between him and Dever-Jakusz.
He told police that he had never seen the detective consume any alcohol or drugs and that he did not think she acted maliciously and that she was just "careless" and "carefree" with the information, according to the report.
During the police interview, the alleged dealer received a text from Dever-Jakusz that said, "I was at wrk and was goin to try to stop by and see ya ... let me know when u home later ... if free will try to come by. at least to say hi."
"On 10/12/2013, the Tempe Police Department terminated the approximate 5 month drug investigation on Mill Avenue after discovering the identities of the involved undercover detectives were disclosed," the report states.
In an Oct. 15 police interview with Dever-Jakusz, she was informed that she was the focus of a criminal investigation.
"Det. Dever-Jakusz initially thought I was joking," a detective wrote in the police report. "I told her it wasn't a joke and said I wanted to talk to her about her association with [the alleged drug dealer's name redacted]. Det. Dever-Jakusz said she was not going to talk."
Text messages on her department-issued cellphone to the suspected drug dealer had been deleted, the report said.
Tempe Chief of Police Tom Ryff emailed a memorandum to Tempe Police employees about the situation in order to "maintain an open and transparent line of communication" throughout the organization but revealed few details due to the ongoing investigation.
"I can confirm that Jess' decision to resign was voluntarily in nature and for reasons which are personal to her and her family," Ryff wrote in the email obtained by ABC News' Phoenix affiliate KNXV-TV.
"I can confirm that an active criminal investigation related to the crime of hindering prosecution was undertaken based upon evidence discovered and as such, the matter was recently forwarded to the Maricopa County Attorney's Office for a charging review," the chief of police wrote.
The Maricopa County Attorney's Office told ABCNews.com they are reviewing the case and have not made any charging decisions yet. The police department has not responded to ABC News' request for comment.