MUSKEGON, Mich. (WOOD) — A new billboard went up in Muskegon Thursday with a message to Kevin Bluhm, the cousin of convicted killer Jeffrey Willis.

The black and pink billboard near US-31 and Laketon Avenue bears three simple words: “Your silence killed.”

“I think it gets the point across,” Jessica Josephson said. “Kevin Bluhm staying silent helped to kill my sister.”

Her sister is Rebekah Bletsch, who Willis was convicted of murdering.

Willis was also convicted of murdering Jessica Heeringa, who vanished from the Norton Shores gas station where she worked in April 2013. Bletsch was shot and killed while jogging near her home in Dalton Township in June 2014.

“Willis is serving his time. Justice has been served there. Now I’m on to Bluhm, ” Josephson said.

Bluhm was charged with being an accessory after the fact in the Heeringa case. In recorded conversations with police, he said Willis called him over to his grandfather’s home after Heeringa disappeared. There, he said, he saw a woman that he knew she was dead “because she was not moving.” He said that Willis told him he had tortured her. Bluhm said he helped Willis wrap her up “like a taco” and then carried her body to a dug hole. He later said he made it all up.

“The details that he gave that he said he saw (Heeringa’s body), it’s just too detailed. You can’t make that stuff up,” Josephson said.

Bluhm’s computer hard drive was missing when police searched his home and his cellphone had been cleared.

Heeringa’s body has never been found.

Bluhm served a little more than a year in jail for lying to police and being an accessory. He’s now back at his Muskegon home on a GPS tether.

“I would eventually like to see Bluhm come forward with some answers. Where is Jessica? What really happened?” Josephson said.

She said she’s angry that Bluhm is able to enjoy time with his family while her sister is gone.

“I hope he has guilt every single day,” she said. “This is pressure and I’m not going to give up on the pressure. This is just the beginning.”

Supporters are putting matching signs in their yards.

“We try and help every way we can,” Bletsch family friend Amanda Falklwski said. “You would think you would wear on you after some time, but I don’t know what kind of person he really is, but I would think it would, though, especially since you have a wife and kids of your own.”

The family would like to add more billboards. You can go to the “Your silence killed” Facebook page to learn how to donate or buy a yard sign.

Next week, Willis will be sentenced to life in prison for Heeringa’s murder. He is already serving a life sentence for Bletsch’s murder.