Nicole Pietz disappeared from her Lynnwood home last January. Her body was found in a wooded area in Burien less than a week later. Police said she had been strangled.

Her killer has not been found.

Video: Pietz Murder Unsolved After A Year

Pietz’s mother, Gael Schneider, said she is talking in hopes of finding justice for her daughter.

“Nobody has the right to take someone else’s life,” said Schneider.

Schneider told KIRO she hopes that whoever helped the person that killed her daughter is filled with guilt.

“The killer doesn’t have a conscience. If there was an accomplice, let your conscience be your guide. To the killer: You’re a monster. You’re a monster,” said Schneider.

Schneider said she believes she knows who the killer is.

“I believe I do (know the killer). But until an arrest is made, I can’t say anything else,” Schneider said.

The last person to see Pietz alive the night she disappeared was her husband, David.

“I worked until 11 p.m. I got home probably around midnight and came to bed and that’s the last time I saw her,” said Pietz’s husband.

Since the murder, David Pietz has never again talked publicly about his wife’s death, and when KIRO contacted his father Thursday night, he said the family had nothing to say.

A King County Sheriff's spokesman said they have more than one person of interest in the case but no suspects.

There is an $11,000 reward for information leading to an arrest.

Meanwhile, Nicole Pietz’s family is preparing for a memorial service to be held this weekend at the Evergreen Community Church in Bothell.

Schneider said friends and family from around the country are coming there to honor her daughter.

The memorial service begins at 10 a.m. Saturday morning.