KALAMAZOO, Mich. (WOOD) — The mother of eight who disappeared more than a month ago had been dating a man whose criminal record includes a murder-for-hire plot, according to those close to her.

From almost the start, police in Kalamazoo County said they had a person of interest they believed knew where to find Heather Kelley, who went missing on Dec. 10.

They wouldn’t identify the man or say how he knew her, though they said he was locked up on an unrelated charge.

Stephen Martin, the father of Kelley’s eight children, told Target 8 she was dating a man at the time she disappeared.

A spokesman for the Federal Bureau of Prisons said the 37-year-old man had been released from federal prison in July and was transferred to “community confinement,” a halfway house operated by the Bureau of Prisons’ Detroit Residential Reentry Management Office.

The man was listed as an escapee from federal custody on Dec. 12, two days after the disappearance, federal records show.

The spokesman told Target 8 he was arrested on Dec. 14 and locked up at the Newaygo County Jail.

Target 8 is not identifying him because he hasn’t been charged in the case.

Kalamazoo County Prosecutor Jeff Getting refused to discuss the man, saying only that he was in federal custody.

Federal court records show he conspired with a former jailhouse acquaintance in 2010 to sell cocaine in Calhoun County to customers steered to them by local prostitutes.

He also was accused of soliciting others to help him murder a drug dealer who had robbed him, records show.

He was sentenced to 13 years in federal prison in 2013 for the conspiracy and on a weapons charge, but records don’t show what happened in the murder-for-hire plot.

In an earlier interview, Stephen Martin Sr., the paternal grandfather of the eight children, begged for the man to talk.

“If you had anything to do with it, confess, get it over with, don’t make people suffer. We don’t know where she’s at,” he said.

Kelley’s name now appears on the federal government’s National Missing and Unidentified Persons Systems database.

NAMUS is a nationwide system set up to link missing persons cases with unidentified remains.

According to NAMUS, the 35-year-old Portage woman told her family she was on her way to pick up an acquaintance in downtown Kalamazoo on Dec. 10 and was last seen at 9:30 that night.

Police found her abandoned vehicle the next day near North Sprinkle Road and East Michigan Avenue in Comstock Township. In it, police found evidence of a violent crime. They didn’t elaborate.

Silent Observer is offering a reward of up to $5,000 in the case. Anyone with information is asked to contact the Kalamazoo County Sheriff’s Office at 269.383.8748 or Silent Observer at 269.343.2100.