Susan Spencer

But did he really do it? Where was Dr. Illis at exactly 10.37 p.m. that Friday night? His years as a hunter have taught District Attorney Michael Dinges a valuable lesson. Having the quarry in sight doesn't necessarily mean it's time to act.

But investigators didn't wait to probe Dr. Illis' alibi. He told them he'd been on the road when Miriam was killed, that after picking up Richie at 5, he left for his sister's house downstate around 9.30.

But investigators didn't wait to probe Dr. Illis' alibi. He told them he'd been on the road when Miriam was killed, that after picking up Richie at 5, he left for his sister's house downstate around 9.30.

But investigators didn't wait to probe Dr. Illis' alibi. He told them he'd been on the road when Miriam was killed, that after picking up Richie at 5, he left for his sister's house downstate around 9.30.

Nevertheless, investigators videotaped and timed the route under good and bad weather conditions. Two minutes, 48 seconds. The key was a stop at McDonald's, 35 miles from the crime scene.

Nevertheless, investigators videotaped and timed the route under good and bad weather conditions. Two minutes, 48 seconds. The key was a stop at McDonald's, 35 miles from the crime scene.

Nevertheless, investigators videotaped and timed the route under good and bad weather conditions. Two minutes, 48 seconds. The key was a stop at McDonald's, 35 miles from the crime scene.

Witnesses saw Dr. Illis there, but were vague as to when, and his story changed.

Witnesses saw Dr. Illis there, but were vague as to when, and his story changed.

Witnesses saw Dr. Illis there, but were vague as to when, and his story changed.

At 11.24, cell phone records show Dr. Illis called his sister. He told her the roads were so bad he was stopping for the night. And hotel records have him checking in around 1 a.m., some 90 miles from Williamsport. So what is wrong with his account of how he was spending those critical hours?

At 11.24, cell phone records show Dr. Illis called his sister. He told her the roads were so bad he was stopping for the night. And hotel records have him checking in around 1 a.m., some 90 miles from Williamsport. So what is wrong with his account of how he was spending those critical hours?

At 11.24, cell phone records show Dr. Illis called his sister. He told her the roads were so bad he was stopping for the night. And hotel records have him checking in around 1 a.m., some 90 miles from Williamsport. So what is wrong with his account of how he was spending those critical hours?

One person may know the truth for sure. Ritchie emerges as your best alibi witness. And yet it took almost two years, in fact, for him to be interviewed. What was the problem there?

One person may know the truth for sure. Ritchie emerges as your best alibi witness. And yet it took almost two years, in fact, for him to be interviewed. What was the problem there?

One person may know the truth for sure. Ritchie emerges as your best alibi witness. And yet it took almost two years, in fact, for him to be interviewed. What was the problem there?

When Dr. Illis finally did let Richie talk, the boy had little to say, and D.A. Dinges thinks he knows why.

When Dr. Illis finally did let Richie talk, the boy had little to say, and D.A. Dinges thinks he knows why.

When Dr. Illis finally did let Richie talk, the boy had little to say, and D.A. Dinges thinks he knows why.

But speculation isn't evidence, and the evidence wasn't adding up too much. Police sent the cigarette butt and three hairs found in the silencer for DNA analysis. But ironically, one of the earliest real leads came from Miriam Illis herself. As do many people during a divorce, she'd made a video inventory of household possessions. Police took special note of Dr. Illis' workshop.