(CNN) -- Nicholas Welch, the man who police say fatally shot a woman near Seton Hall University in New Jersey, will be arraigned Wednesday.
Essex County prosecutors have charged Welch, 25, with murder, conspiracy to commit murder and weapons charges.
Four counts of attempted murder are expected to be added by the time of the arraignment Wednesday morning, said Acting Prosecutor Robert Laurino.
On Tuesday, Welch proclaimed his innocence 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 returned with a gun, kicked in the door and opened fire on about 50 college students inside, said Laurino.
Jessica Moore, a sophomore honors student from Virginia, died in the shooting. Four others suffered non-life threatening wounds, authorities said.
CNN's Jason Kessler contributed to this report.