LYNNWOOD — Her son found her battered body inside her Lake Stickney home.

Madeline Johnson, 73, had been beaten to death with the blunt end of an ax. Her son, a former Seattle police detective, told Snohomish County investigators he suspected that someone tried to make it look like his mother was killed during a burglary.

The investigation took a devastating turn for the family.

Johnson’s grandson, 30, was arrested and charged with first-degree murder for the 1980 brutal slaying.

The case would take another surprising turn.

Prosecutors were forced to drop the charge against the suspect after he married the prosecution’s key witness during a jailhouse ceremony. The witness was expected to testify that she’d heard the man confess to the killing, prosecutors said at the time. Once married to the man, the law then in place protected the woman from taking the stand against him.

Johnson’s death remains an open investigation.

The Lake Stickney woman is featured in the state’s first cold-case deck of playing cards. Johnson is on the Five of Hearts. The cards have been handed out to prison and jail inmates in hopes of soliciting new leads for unsolved homicide and missing persons cases. The cards feature crimes dating back to the 1970s.

Johnson’s family is hopeful someone will step forward with information about the killing. Detectives spoke with Johnson’s son earlier this year before his death in June about their renewed efforts to catch the killer. He was encouraged about the cards, relatives said.

“He’d be hopping up and down if something comes out of this,” a relative said.

Madeline Johnson owned an ice cream shop called Neptune Freeze near the Mukilteo ferry dock after retiring from Boeing. She was kindhearted and always willing to help anyone who needed a hand, her family said.

“You never get over it. It’s still there,” a relative said. “You’d like to see justice for her.”

Reporter Diana Hefley: 425-339-3463 or hefley@heraldnet.com.

About this series

Snohomish County sheriff’s detectives created the state’s first deck of cold-case playing cards. Each Sunday for a year, The Herald is publishing a story about a case featured on one of the cards. To see the 52 cards, go to www.heraldnet.com.

Anyone with information about unsolved homicides or missing persons cases is asked to call 800-222-TIPS (8477). A reward of up to $1,000 is offered.

Tips also can be left on the sheriff’s tip line at 425-388-3845. Callers may remain anonymous, although tips have been more successful when callers speak with detectives, police said.