A Marine veteran with a history of mental illness pleaded guilty yesterday to attempted murder in last year's South Philadelphia road-rage shooting that left a South Jersey man disabled with a head wound.

Christian Squillaciotti, 34, pleaded guilty to two counts of attempted murder and possessing an instrument of crime in the Oct. 5, 2008, vehicular duel on the Schuylkill Expressway that critically wounded Thomas Timko, 42.

Philadelphia Common Pleas Court Judge Rose Marie DeFino-Nastasi set sentencing for Feb. 5.

The judge told Squillaciotti that he faced a maximum sentence of 40 years in prison for the attempted murder count involving Timko and 20 more years for the count involving Timko's daughter Kaitlin, 8, a passenger who was not physically injured, plus five years more on the weapons charge.

Squillaciotti, a hulking 6-foot-4 and 275 pounds, said nothing during the 15-minute hearing except to confirm, "Yes, ma'am," with military crispness as the judge asked if he understood the rights he waived by pleading guilty.

Unlike his preliminary hearing in September, when Squillaciotti seemed so heavily medicated he could barely focus, he seemed alert and focused.

Assistant District Attorney Thomas Lipscomb and defense attorney Christopher J. Angelo agreed that Squillaciotti should be returned to Norristown State Hospital pending sentencing.

Angelo has said that Squillaciotti has had a history of untreated schizophrenia and personality disorder since he was 19. Angelo said he believed Squillaciotti has also suffered from post-traumatic stress disorder since his 1994 combat experience in Haiti.

Police said Squillaciotti pulled along the passenger side of Timko's 2001 Toyota Highlander SUV moments after the two vehicles got onto the Schuylkill Expressway from the Walt Whitman Bridge near Passyunk Avenue.

Police say Squillaciotti fired four shots at the SUV, shattering the rear passenger window, and one shot hit Timko in the head.

The shooting followed a vehicular duel between the drivers that began in South Jersey and ended in South Philadelphia. Though Timko has recovered enough to walk and talk, prosecutors say he suffered significant cognitive problems from the wound.