The man charged with the murder of SF State student Justin Valdez pleaded not guilty to three felony counts Tuesday at the Hall of Justice, one month after new evidence was presented against him.

Public defender Robert Dunlap entered the plea on behalf of Nikhom Thephakaysone in response to charges of assault with a deadly weapon, possession of an illegal assault weapon and the murder of Valdez.

Superior Court Judge Bruce Chan said at the arraignment hearing that Thephakaysone willfully and illegally discharged his weapon on the night of Sept. 23, 2013, when the suspect allegedly shot the 20-year-old student as he exited the M-Oceanview Muni train at Randolph and Bright streets.

Thephakaysone, who also attended SF State at the time, was arrested by police the day after the incident at his Oceanview home where officers found assault weapons, four knives and $20,000 in cash.

During his preliminary hearing last month, investigators connected two of Thephakaysone’s fingerprints to an ammunition magazine, but said only one was usable for analysis and identification.

Additional evidence revealed in court by Assistant District Attorney John Rowland included photographs, the .45 caliber handgun and a bullet casing.

Crime scene investigator John Evans said at the Nov. 8 hearing that the firearm and magazine were found in a storm drain at the intersection of Orizaba Avenue and Lobos Street, less than a block away from where the shooting happened.

The firearm number had been obliterated or defaced, according to Evans, and the .45 caliber handgun was unloaded when they found it.

Forensic pathologist for the medical examiner Ellen Moffatt, who was at the scene of the crime, said that Valdez was not killed as a result of a gunshot wound to the back of the head, but from a gunshot wound to his back. She concluded that Valdez’s death was a homicide.

A Muni surveillance video from before the incident shows both Thephakaysone and Valdez on the same train, with no sign of interaction between the two before the shooting.

A sustainability advocate and member of the water polo team and Dragon Boating Club on campus, the sophomore was an active member of the SF State community, Xpress previously reported.

Thephakaysone transferred to SF State in Fall 2008 and was enrolled in Open University classes. He is set to appear back at the Hall of Justice Feb. 6 at 2 p.m.