PHOTO: Tommy Gilbert attends The School of American Ballets 2014 Winter Ball at David H. Koch Theatre in New York, March 3, 2014.

The death of a hedge fund manager was “staged” to look like a suicide, according to police who are questioning the dead man’s son for a second day today.

Thomas Gilbert, the 70-year-old founder of Wainscott Capital Partners, was found shot dead in his Manhattan apartment Sunday night and police took his son Tommy Gilbert, 30, into custody around 10:45 p.m. Sunday, authorities said.

Tommy Gilbert was still being interrogated by police at the 17th precinct as of noon today, a spokesperson for the NYPD told ABC News. The spokesman said that no charges have been filed in the case.

The medical examiner has not yet ruled whether the death was a homicide, but two officials briefed on the investigation tell ABC News that detectives now believe Gilbert was the victim of a homicide and that the scene was “a staged suicide.”

Detectives believe the elder Gilbert was killed by his son, who then left the murder weapon – a .40 caliber Glock 22 — in the bedroom to make it look like a suicide, sources told ABC News. The gun was found in the bedroom near the victim’s body, but the weapon’s case was allegedly recovered in the son’s apartment, sources said.

Police said the son entered his parent’s Beekman place home Sunday afternoon and asked his mother to get him a sandwich. The mother told police that she left the apartment, and when she came back, she discovered her husband shot in the head in his bedroom.