"48 HOURS" INVESTIGATES TWO MURDER CASES THAT EXPOSE DARK SECRETS IN A SATURDAY NIGHT DOUBLE FEATURE

"Death on the Hudson" - 9:00 PM, ET/PT

"The Strange Life of Dr. Schwartz" - 10:00 PM, ET/PT

Correspondent Peter Van Sant and 48 HOURS investigate two murder cases that expose deep secrets in a Saturday mystery double feature, to be broadcast Saturday, July 29 on the CBS Television Network (9:00 PM-10:00 PM, ET/PT).

At 9:00 PM, Van Sant and 48 HOURS explore serious questions in the case against Angelika Graswald, who was charged with killing her fiancé, Vincent Viafore, during a kayaking trip, and the stunning resolution that shocked his family, in an updated encore of "Death on The Hudson."

The couple went out for a kayaking trip on the Hudson River in Cornwall, NY in April 2015. Graswald returned from the trip, Viafore didn't. Graswald said that the weather changed while they were on the river and Viafore's kayak capsized. Viafore wasn't wearing a vest; she said he disappeared under the water.

Police maintained that his kayak was missing a plug that allowed water to fill his boat as he desperately tried to return home. Investigators maintained Graswald killed Viafore because she stood to gain $250,000 in insurance payouts and that their relationship had soured. Investigators also said she made statements that implicated her in the crime. Her defense team argued Viafore's death was an accident, nothing more, and the plug in the kayak police say led to his drowning was removed long before the incident. Her attorneys said that the size and position of the hole for the plug took in less water than the open well of the kayak did in rough water.

Was Viafore murdered or was his death a tragic boating accident?

"Our investigation has uncovered evidence that may change people's perception of the case and bring into question whether a murder occurred," Van Sant reported.

At 10:00 PM, Van Sant and 48 HOURS investigate the brutal murder of Dr. Steven Schwartz, a beloved Florida physician who ended up dead in his Tarpon Springs, Florida mansion, in an encore of "The Strange Life of Dr. Schwartz."

Schwartz was a wealthy, well-respected kidney specialist who had a successful real estate venture with his second wife, Rebecca. But everything changed on the evening of May 14, 2014, when Mrs. Schwartz dialed 9-1-1 to report her home had been robbed. When police arrived and began checking out the crime scene, they found Schwartz dead. He'd been shot, stabbed and beaten.

The investigation into what happened would uncover a family with strained relationships, competing allegations on what may have happened, and a whole secret life that Schwartz had hidden from his offspring.

A year after the murder, police arrested Leo Anton Stragaj, a builder, who worked on the family's nearly 40 properties. Police found Stragaj's DNA on Schwartz' body. Stragaj admitted seeing Schwartz' body that day, but did not call police. He fled the scene, he said, because he was an immigrant and didn't want to do anything to jeopardize his record.

"I didn't do it. I did not kill the man. I didn't commit the murder. I was set up," Stragaj tells Van Sant in an extensive jailhouse interview. Instead, he told 48 HOURS, Schwartz' wife had something to do with the murder. Rebecca Schwartz declined to be interviewed by 48 HOURS. However, her attorneys said their client is innocent and allege Stragaj used Schwartz to deflect from his own guilt.

So what really happened to Dr. Steven Schwartz? And did something that occurred 50 years in the past have something to do with the murder?

48 HOURS: "Death on the Hudson" is produced by Patti Aronofsky, Elena DiFiore and Lourdes Aguiar. Gregory McLaughlin is the producer editor. Ryan Smith and Kathleen O'Connell are the development producers. Linda Martin is the update producer. Al Briganti is the executive editor. Susan Zirinsky is the senior executive producer.

48 HOURS: "The Strange Life of Dr. Schwartz" is produced by Alec Sirken, Ryan Smith and Michelle Feuer. David Spungen, Grace Arlotta-Berner and Ken Blum are the editors. Linda Martin is the update producer. Anthony Batson is the senior broadcast producer. Susan Zirinsky is the senior executive producer.

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