Ontario police release sketch of suspect in unsolved, 1988 murder of Thera Dieleman

Composite sketches of a killer are provincial police’s latest hope in solving the murder of an elderly Innerkip-area woman 30 years ago.

Thera Dieleman was found beaten and strangled in her Blandford-Blenheim Township home, the afternoon of Sept. 16, 1988. OPP say her last known contact was a phone call around 5 p.m. the evening before, just a few minutes after she’d been dropped off after a day of shopping in Goderich with friends.

During a media conference at West Region OPP headquarters, Det. Supt. Ken Leppert said the original investigation narrowed the timeline in which the elderly widow and Second World War internment camp survivor was killed.

“Rural mail delivery had already occurred at 10 a.m. that morning. This mail was found within Mrs. Dieleman’s residence, and had been opened,” he explained.

Thera Dieleman was murdered in 1988.

Thera Dieleman was murdered in 1988.


But at 11:10 a.m., and 11:30 a.m., a relative’s calls to Dieleman’s home went unanswered, he said.

Shortly after those phone calls, between 11:45 a.m. and 12 p.m., police say witnesses walked by the Dieleman home, where the victim lived alone, and saw a red or brown flatbed farm truck with white lettering, dual rear wheels, and a black headboard protector behind the cab.

“Thera put up a fight during the attack, potentially causing injuries to her attacker,” said Leppert.

There’s no evidence to suggest Dieleman knew her attacker, or was the subject of a robbery, explained Leppert. He wouldn’t say whether the victim was sexually assaulted.

Last summer, provincial police contacted DNA technology company Parabon Nano Labs and sent suspect DNA discovered on Dieleman’s body. The lab generated two composite sketches, released Tuesday.

Photo of a flatbed truck that resembles the suspect vehicle.

Photo of a flatbed truck that resembles the suspect vehicle.

The first photo is what the suspect may have looked like at 25 years old, and the second photo is what he might look like now, said Leppert.

But it’s only a rough estimation of what the individual might look like. Predictions were made about the subject’s ancestry, eye colour, hair colour, skin colour, freckling, and face shape, he explained. But the sketches also employ default values for age and body mass, because those things can’t be determined by DNA.

“The composite sketches in this manner are scientific approximations of appearance based on DNA, and are not likely to be exact replicas of appearance,” said Leppert.

“Environmental factors, such as smoking, drinking, diet, and other non-environment factors like facial hair, hair style, scars, cannot be predicted by DNA analysis.”

Leppert is urging people to spend time looking at the photo, in hopes of “igniting memories” that might help police crack the case.

“It’s amazing how what one person might see to be very insignificant can be very critical when combined with other pieces of evidence,” he said.

Anyone with information about the case is urged to contact a dedicated tip line at 1-844-677-9414 or Crime Stoppers at 1-800-222-8477 (TIPS).

© 2018 Global News, a division of Corus Entertainment Inc.

You May Also Like

Top Stories