A 21-year-old Hempstead man pleaded not guilty Tuesday in Nassau Criminal Court to second-degree murder and gang assault charges for his alleged roles in two shootings.

The shootings occurred in July and September of 2022.

Police say Gerson Hernandez is a member of MS-13. He's accused of killing Walter Ochoa Jr while he was sitting on a bench at Uniondale Avenue Park on July 19, 2022.

They say he was involved in a gang assault two months later that led to the shooting death of Hector Manual Valencia Gomez, 19, of Hempstead. That occurred at a McDonald's parking lot on Peninsula Boulevard Hempstead in Hempstead on Sept. 14.

In a briefing Tuesday, Nassau County police say Hernandez did not pull the trigger in the second shooting but that he was at the scene.

Hernandez's lawyer says his client denies "shooting anyone, stabbing anyone" and that he has received "very little information" about the charges.

Capt. Stephen Fitzpatrick, of the Nassau Police Homicide Squad, says they have video surveillance evidence, DNA and a weapon recovery in the Hempstead case. He says they also have eyewitnesses and cooperating people.

Nassau police are asking the public to help find another suspect named Wilson Yanes, 18, of Hempstead, who is wanted in the alleged gang assault. Police believe he could be here locally or in the Virginia or Maryland areas.

In February, Hernandez was arrested in Maryland on a bench warrant for an assault case in November 2020.

Hernandez also faced assault charges in 2020. He's expected back in court on Thursday.