The body was later identified as 25-year-old Roosevelt Rene, who is a family friend of Jenkins, according to police. Rene had reportedly been living at the house of late.
The police did not reveal a cause of death.
According to multiple reports, police are treating the investigation as a homicide. NFL Network's Mike Garafolo reports police are investigating "a possible strangulation/suffocation as the cause of death," citing law enforcement sources.
Multiple reports say Jenkins is not in New Jersey and has been staying in Florida.
According to ESPN's Dianna Russini, Jenkins has been in Florida since the Giants broke from their offseason practices, which ended June 14. That report adds that Jenkins had family staying in the New Jersey home and he had plans to return to New Jersey today "to deal with this situation" but might stay in Florida.
TMZ reports the body was found in the basement by a person who was working on the house.
Authorities received a 911 call at 10:22 a.m., Fair Lawn Police Sgt. Brian Metzler said. The body was removed from the property just before 8 p.m.
Jenkins, 29, is entering his third year with the Giants. The Pahokee, Fla., native played for Florida in college before finishing his career at North Alabama.
A Giants spokesperson confirmed the team is "aware of and monitoring the situation."
--Field Level Media