The memories come back to Mary McKenna in odd ways. She'll bump into a special-education teacher or a social worker who once helped her foster daughter, Deltrece Benson.

She has gotten random calls from the homicide detective who first caught the case, and a call from one of the early suspects, who later was cleared. Feb. 10 marked the 25th year since Deltrece, age 12, was murdered, found by the landlord alone in the family's apartment with two scarves tied around her neck.

And for the 25th year, McKenna grieved and wondered what more she could do to coax a witness forward. As she always does, she went downtown to the homicide unit of the Minneapolis Police Department and gave the detective handling the case, Sgt. Darcy Klund, a plant with a purple ribbon, Deltrece's favorite color.

It's both a thank you to the officers for their work on the case and a reminder that justice still has a score to settle.

The murder of Deltrece has been a mystery for as long as the missing-person case of Jacob Wetterling, but few have heard about Deltrece. McKenna has spoken, appeared and exchanged hugs with the Wetterlings many times over those years.

Like the Wetterlings, she knows if there is any hope of finding the person who did it, she needs to keep bringing the case to the public. I wrote about the effort by Mc­Kenna and police five years ago, and told her I would try again, in case there is someone out there who knows something.

When she was murdered, police believed, and still believe, that the killer was someone familiar. While her mother, Jodi Benson, was out that night, she let the killer into the apartment.

When Benson called home to check on her daughter, there was no answer. So the mother called the landlord, who discovered the body.

Police initially arrested a 15-year-old boy on suspicion of the murder, but released him when the facts didn't match, McKenna said.

"I actually remember the case well because it was one of the few we didn't solve," said Brad Johnson, who went on to head the city's homicide unit. Johnson, now retired, said "the case does still bug me."

When Deltrece was younger, Benson struggled to care for her, so child protection workers moved the girl to the McKenna home in Prior Lake.

Deltrece was eventually returned home but continued to spend every other weekend with her foster family as "respite" for her mother, and a chance to continue the relationship with the McKennas, who grew close with the girl despite their different backgrounds.

"My sons are now 32 and 34, and the murder has greatly affected their lives," said McKenna. "She was a big sister to them."

Deltrece grew while she was with the McKennas.

"She played basketball and softball," said McKenna. "She joined the Girl Scouts. I still run into some of her classmates and they have families and kids — the kind of life she could have."

All of them ask about Deltrece, and about any progress on her case.

"You forget the ripple effects you have on other people," McKenna said. "She was quite entertaining for a 12-year-old. She did a lot of living in a very short time."

McKenna said Deltrece was captivated at breakfast by the pictures of missing kids on milk cartons. She did not foresee that her foster mom would one day share grief with the mother of Minnesota's most famous missing child.

"She wanted to do something for missing kids," said McKenna. "She wanted to be somebody like John Walsh," host of "America's Most Wanted" and head of the National Center for Missing and Exploited Children.

Maybe Deltrece's dream was a good omen. The detective who now has her case, Klund, was named an "All Star" by Walsh's show in 2011 for his work to solve the 1990 stabbing of 11-year-old Marcus Potts in 2006, and his persistence in solving the 2003 shooting death of Marcus Dortch, whose killer was convicted in 2010.

Klund says solving a case that's been cold so long will take continued diligence and some luck.

"It's going to take somebody coming forward that knows more than what's being said," said Klund. It's highly likely the killer has told someone, Klund said. He's had cases where a witness finds a conscience, or maybe gets arrested themselves and gives up the suspect to cut a deal.

"There is nothing I would like [more] than to have one of those moments," Klund said. People may have information on the case and "don't know the value of what they have."

Whenever police solve a cold case, it tends to elicit a lot of calls from other families with open cases. "It sort of revives things for the families because it gives them hope. It reassures the families that we are still working on cases and gives the public the sense we are never going to give up."

But Deltrece never got the chance to follow any dream. She was buried at Hillside Cemetery. Her headstone reads, "Don't worry, be happy."

jtevlin@startribune.com • 612-673-1702

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