By Alecia Reid

PHILADELPHIA (CBS) — A family’s search for answers continues on the one-year anniversary of the murder of a Delaware County high school teacher. Eyewitness News spoke with the family of Susan Ledyard on Saturday as the Academy Park teacher’s homicide remains unsolved, but there’s new information that Ledyard’s family hopes can help crack the case.

The new information includes a critical four-hour period that investigators believe could help lead to her killer.

“There have been people of interest, but there has not been anybody who has risen to the level of a suspect,” John Morrissey, Ledyard’s brother, said.

It’s been a year since Ledyard’s murder.

(Credit: CBS3)

“I love my sister so much,” Morrissey said. “She was the coolest kid around. I thought she was the coolest person in the world.”

Investigators in the Ledyard case have uncovered new evidence that shows the 50-year-old was wearing a Fitbit tracker that accounted for the time she was last seen on surveillance at 3 am. until 7 a.m.

“It’s because of that, that we know there are those four extra hours, which leads up to the time very shortly before she was found,” Morrissey said. “I’m not sure what time the sun rose that day, but it’s those four hours on the morning of July 23, 2019, where we still don’t have enough information.”

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Those four hours are unaccounted for, but investigators believe Ledyard may have been alive until shortly before her body was found by a construction worker in the Brandywine River in Wilmington, Delaware.

“Even though the fitness tracker that has given us that information, we feel there’s more information that Fitbit can give us about more details about what happened during those four hours,” Morrissey said.

Ledyard grew up in Kennett Square and graduated from Tatnall School in Wilmington.

Delaware State Police determined the former teacher died from blunt force trauma to the head and drowning. Her car was located three miles upriver.

Detectives do not believe she entered the river where her vehicle was parked.

Ledyard’s family believes someone out there may have seen something that seems insignificant but could actually be the lead investigators need to break the case.

If you have any tips, whether big or small, you’re urged to call Delaware Crime Stoppers at 1-800-TIP-3333.