The case of a missing Missouri mother is now officially a death investigation, prosecutors said.

Renee Pernice, 35, vanished Jan. 1. She was last seen by her husband Shon Pernice.

"We believe foul play is involved," Clay County Prosecutor Daniel White said Thursday.

Existing evidence and the amount of time that has passed since the woman's disappearance led prosecutors to change the status from a missing persons case to a death investigation, White said.

No one has been arrested in the case. Shon Pernice, a local firefighter and an Army medic who had recently returned from service in Iraq, has given different dates for when he last saw his wife, police have said.

He told relatives he last saw Renee Pernice on Jan. 1, but said it was Jan. 2 when questioned by detectives, according to court documents.

Renee Pernice was in the process of divorcing her husband, who was planning to move out of the house at the end of January, relatives say.

The missing woman's family offered a $25,000 reward for new information about her disappearance, FOX4KC.com reported.

"We can't stress enough how we need someone's help out there someone who knows something," said Linda Lockwood, Renee's mother.

Last month, investigators collected carpet and blood samples from the couple's home. When they searched the house Jan. 8, they discovered latex gloves in a coat pocket, stains on a pants pocket, a reddish substance on the ceiling and a spot in the garage that turned out to be blood.

"The perpetrator of this crime, I think they know they have some new heat on them," Rick Pretz, Renee's father, told FOX4KC.com. "You can't come up with a reason why Renee isn't with us. (She) just had not done anything wrong."

Click here for more on this story from FOX4KC.com.

The Associated Press contributed to this report.