Motorcyclist dies after going over I-45 ramp onto US-59 in Downtown Houston

HOUSTON - A motorcyclist was found dead Tuesday night in Downtown Houston after police believe he fell from an elevated ramp.
Deadly motorcycle crash
What we know:
Lieutenant Willkens says they received reports of a crash around 11:35 p.m. around I-45 and US-59 near Gray Street, but officers had trouble finding the scene.
Eventually, officers located the rider on the side of US-59 North near Pierce Street. He was pronounced dead at the scene.
According to police, they suspect the motorcyclist was going southbound on I-45 and took the elevated ramp to get on US-59 going northbound. Evidence shows the rider possibly went over the railing and landed in the grassy area below.
What we don't know:
It remains unclear what caused the motorcycle to go over the railing.
Authorities have not yet released the victim's identity.
The Source: Houston Police Department Lieutenant Willkens.