(CNN) -- The man accused of fatally shooting a woman at a party near Seton Hall University in New Jersey pleaded not guilty to murder Wednesday in his first court appearance, Essex County prosecutors said.
Nicholas Welch, 25, had proclaimed his innocence Tuesday as police officers escorted him to a waiting squad car.
"I am innocent. I didn't do it," he said.
The shooting occurred at an off-campus party in East Orange -- about a mile from the Seton Hall campus -- at 12:17 a.m. Saturday, officials said.
Welch had been denied entry to the party, authorities said. Angry, he allegedly returned with a gun, kicked in the door and opened fire on about 50 college students inside, officials said.
Jessica Moore, a sophomore honors student from Virginia, died in the shooting. Four others suffered non-life threatening wounds, authorities said.
At his arraignment Wednesday, Welch entered not guilty pleas to all the charges he is facing: murder, conspiracy to commit murder and weapons charges.
Meanwhile, a second suspect in the shooting was arrested Wednesday, authorities said. Marcus Bascus, 19, of East Orange was taken into custody without incident in Wilkes-Barre, Pennsylvania.
Bascus will face charges of murder, conspiracy and weapons violations. Bail was set for $2 million, authorities said.
CNN's Chris Kokenes contributed to this report.