The would-be hit man got cold feet.

He was onboard when a 29-year-old Depew woman, whose car he sometimes repaired, offered him a different type of job – $1,000 to kill her meddling mother-in-law, whom she blamed for her failing, three-year marriage.

Jean M. Rzeznik-Stanton figured that the mechanic could fix things, police said, but it didn’t work out that way. He changed his mind.

Now Rzeznik-Stanton, a licensed practical nurse and mother of three, is charged with second-degree conspiracy to commit murder, following a lightning-fast sting operation by Buffalo Police Department Intelligence Unit detectives.

The murder-for-hire plot began about a month ago, when Rzeznik-Stanton offered the mechanic, who is also a family friend, $1,000 to kill 54-year-old Rosemary A. Stanton, of Buffalo, according to police. If that killing “worked out,” the daughter-in-law allegedly promised the mechanic more of the same type of work.

Rzeznik-Stanton’s anger extended to two other members of her husband Michael’s family, according to Detective Sgt. David M. Lillis.

“She also wanted to have her husband’s sister and a goddaughter of her mother-in-law killed and was willing to pay $1,000 each for those killings,” Lillis said.

By killing the grown sister and goddaughter, Lillis explained, Rzeznik-Stanton believed she would maintain custody of the three young children she has with her estranged husband, if by chance he went ahead and left her.

He was still living with her but was in the process of making arrangements to move out of their home on the 5200 block of Transit Road in Depew, Lillis said.

The mechanic, whose name is being withheld by police, was initially intrigued by Rzeznik-Stanton’s offer. She told him he would be paid with cash she expected from an anticipated lawsuit settlement in a personal-injury accident. But as he continued to mull over the proposition, he got cold feet and contacted Rosemary Stanton and informed her of the daughter-in-law’s offer to hire him to kill her.

Alarmed at the murder-for-hire plot, Rosemary Stanton went to the South District police station on Tuesday of last week and met with District Detective Dawn Lopez. She took a statement from the mother-in-law and then notified the Intelligence Unit detectives who jumped on the case.

The detectives interviewed the mechanic, and he agreed to cooperate in a scenario that included a secretly recorded phone call to Rzeznik-Stanton and a rendezvous with her where the mechanic would introduce the daughter-in-law to someone else more willing to do the job. That second “hit man” was actually Detective Jason M. Mayhook. “They met at Bailey Avenue and Clinton Street and got in the car with Detective Mayhook. They then drove to where Rosemary Stanton lives, and Rzeznik-Stanton pointed the house out on Bailey Avenue,” Lillis said.

The ruse continued until they returned to Bailey and Clinton, where Rzeznik-Stanton was placed under arrest. She was taken to Buffalo Police Headquarters, where she confessed, police said.

“She was surprised at first but admitted to participating in the murder-for-hire,” Lillis said, adding that the investigation was carried out in a rapid one-day operation that required several detectives and police officers in addition to guidance from the Erie County District Attorney’s Office.

Rzeznik-Stanton, employed by a health care agency that provides residential nursing services, was released three days ago from the Erie County Holding Center on $15,000 bail.

Her case, pending in Erie County Court, will be presented to a grand jury, authorities said.

Assisting in the case were Intelligence Unit Detectives Earl E. Perrin, Craig J. Leone, Kevin F. Maloney; Narcotics Unit Detectives Leo McGrath, Anthony J. LaPiana, Carmen D. Clark, William J. Gambino, Mark K. Locicero, and Jeffrey R. Weyand, plus South District Officers A.J. Szymkowiak II and Natasha T. Anderson.

“Our Intelligence Unit detectives probably saved a life or two,” Police Commissioner Daniel Derenda said. “They did an excellent job.”