Gina Barton

Milwaukee Journal Sentinel

After months of testing, DNA experts at an Ohio lab have been unable to identify the person who killed 14-year-old John Zera in 1976.

“Nothing to crack the case,” said Hales Corners Police Chief Eric Cera.

Additional tests are being conducted. But the clothing and biological samples that held the best hope of identifying John’s killer did not yield a usable DNA profile, either because they were improperly preserved, became contaminated or simply broke down in the 40 years since John’s death.

John's older brother, Mark Zera, said he wasn't surprised by the lack of progress. The results from the private lab were received earlier this month.

"It is what I expected," he said.

John disappeared from Franklin High School on Feb. 20, 1976. His body was found on the Hales Corners side of Whitnall Park eight days later; police suspected he had been sexually assaulted. Issues with evidence collection, tunnel vision and a long, strange list of suspects have confounded police ever since.

The case was the subject of the 2015 Milwaukee Journal Sentinel series “Unsolved” and an accompanying podcast.

Questions from the news organization were among the factors that prompted police to reopen the case and contract with the Ohio lab for technologically advanced forms of DNA testing. Dozens of tips also were called in to police in the wake of the series.

One suspect who has held investigators’ focus off and on for decades is Daniel Acker, a swim coach at a suburban recreation department whom police questioned in the 1970s. Acker denied killing John and befriended John’s parents in the months following his death.

In 2009, police looking into claims Acker had molested several teenage boys found model police and fire stations plastered with photos of dead and missing children in his basement. Children’s names, including John’s, were inked onto the bottoms of model cars. A journal spanning decades that focused on John’s murder and a photo album about John’s case also were found inside Acker’s house.

After Acker was convicted of child molestation and sentenced to 20 years in prison, he again denied killing John or even having met him, saying the items in his home were tributes to John and to the other child victims.

One of the items tested for DNA, a belt, was collected by Greenfield police as part of the child molestation case and turned over to Hales Corners police late last year as part of the cold case investigation into John’s death.

The belt, which would fit a skinny teenager, matched the description of a belt mentioned in one of the police reports about John’s case. No DNA was found on the belt, which was examined at the State Crime Laboratory, Cera said. Similarly, a cache of items removed from John’s school locker contained no usable DNA.

Scientists at DNA Diagnostics Center, the private lab hired by Hales Corners at a cost of about $10,000, were optimistic about the potential for new evidence on 17 pubic hairs collected from John’s body. But the hairs were mounted on slides, and scientists could not remove the cover slips from those slides without destroying any DNA that may be present on the surface of the hairs.

As was the case with earlier analysis at the state crime lab, the Ohio scientists found no trace of sperm on slides purported to contain it.

Oral swabs contained so many different DNA markers they must have been contaminated, the scientists concluded.

Further testing is planned on several items of John’s clothing that initially came up inconclusive, including the pockets of his jeans, his socks and his flannel shirt.

Although the new testing won’t be able to extract a full profile that could identify the killer, it could yield less precise results, which police could then compare to Acker and other suspects.

"We have gotten more DNA than we had in the past, but at this point there has to be further testing to determine whether it is valuable or useful," Cera said. "It's a long process."

Read the series

To read the Milwaukee Journal Sentinel's "Unsolved" series, which examines the cold case murder of 14-year-old John Zera, go to jsonline.com/unsolved.