Helen Regene McPherson was killed in her Vero Beach home 8 years ago

VERO BEACH, Fla. - Tuesday marks eight years since the murder of a grandmother in Vero Beach. Her killer hasn't been found but police have vowed to solve the case.

Helen Regene McPherson was last seen alive at her home on 49th Avenue in Vero Beach.

"We want justice," says daughter-in-law Wanda McPherson, "We want to know why."

It's a question her family has been asking for eight years.

"It's constantly on my mind," says Wanda McPherson.

Helen McPherson's son Doug and his wife Wanda remember the night of July 14, 2006. They went out to dinner, watched TV at Helen's house and then left around 8:30 p.m.

"I said be sure and lock your door," recalls Wanda McPherson.

The next day the couple went to the house to check on Helen after a neighbor called them because she saw a screen missing from a door. Wanda McPherson remembers walking into Helen's bedroom.

"A mess in the room," says Wanda McPherson, "Things had been turned upside down. She was lying against the wall. There was blood on her face."

Investigators say the 86-year-old was beaten and strangled. The Indian River County Sheriff's Office has had dozens of officers on the case but so far no arrests. 

"Would give us some relief," says Doug McPherson.

Helen McPherson is never far from investigators' minds. Capt. Darin Jones sees her picture every day. It's posted in his office.

"She was somebody's grandmother and I have a grandmother," says Capt. Jones.

The sheriff's office says it's not a cold case.  They're still actively working on it and hoping for a break. 

"It's my neighborhood," says Capt. Jones, "When this heinous crime occurred it hit home for me."

Sheriff Deryl Loar has vowed to find the person who murdered Helen. He says they won't rest until the killer is locked up.

"This is high on our list," says Sheriff Loar, "We will find the killer."

Every year her family pays for an ad in the local newspaper. It's a reminder of what happened to Helen McPherson and a plea for someone to come forward with information.

There is a reward for information that leads to an arrest. If you know anything, call Treasure Coast Crime Stoppers at 1-800-273-8477.