By Hazel Sanchez

NEW YORK (CBSNewYork) — The man accused in a deadly stabbing spree on the A train has confessed to the crimes, prosecutors say.

On Saturday, police arrested 21-year-old Rigoberto Lopez, a mentally ill homeless man, whom prosecutors say confessed to using a knife to stab four people, all said to be homeless, during a 14-hour period beginning Friday morning.

Two men survived. One man and one woman died.

RELATED: 21-Year-Old Rigoberto Lopez Facing Murder Charges For Subway Stabbings On A Train Line

Lopez was ordered held without bail after undergoing psychiatric evaluation at Bellevue Hospital. He faces murder and attempted murder charges.

(credit: Image via CBS2)

A vigil was held Monday afternoon at the 207th Street station in Inwood to remember the victims.

“The people who died and were attacked in our communities did not have to meet that tragic fate. This system, our current system, has failed them,” Assemblywoman Carmen De La Rosa said.

RELATED: NYPD Investigating Series Of Subway Stabbings On A Train Line That Left 2 Dead, 2 Hurt

The father of one of Lopez’s alleged victims said the arrest is not enough.

Claudine Roberts’ body was discovered on a train at the 207th Street station. Prosecutors say Lopez stabbed the 44-year-old a total of seven times, in the chest, abdomen and arm.

Her father, Winston Roberts, said his daughter was homeless, had been hospitalized for her mental illness and was released just days before her murder. He added the city didn’t do enough to help her.

“They need to fix the problem … and they’re not doing it,” Winston Roberts said.

On Saturday, the NYPD added 500 uniformed officers to patrol the subway system. The Metropolitan Transportation Authority is calling on Mayor Bill de Blasio and Police Commissioner Dermot Shea to add an additional 1,000 officers to the Transit Bureau to patrol subways and buses.

RELATED: Demanding Answers: New Yorkers Grow More Concerned About Subway Crime, Curtailed NYPD Involvement In Mental Health Crisis

On Monday, MTA Chairman Pat Foye, speaking before Gov. Andrew Cuomo, made an additional plea.

“We also need more mental health resources from the city of New York, dedicated to address the growing crisis facing the city, so that those suffering have access to the critical services they need and deserve,” Foye said.

Hazel Sanchez