US manhunt for Iraq war vet wanted for 6 murders

US police stepped up a manhunt Tuesday for an Iraq war veteran wanted for the murders of his ex-wife and five of her relatives near the northeastern city of Philadelphia.

Bradley William Stone, 35, is "armed and dangerous" and residents in Montgomery County, Pennsylvania were ordered to stay at home with their doors locked, authorities said.

Law enforcement officials have released a photograph of Stone which shows the former US Marine who served in the Iraq war with closely cropped red hair, a beard and mustache.

Prosecutors say Stone, who allegedly carried out the killing spree in three separate communities, uses a cane or a walker and was possibly wearing military fatigues.

State police concentrated the manhunt overnight in Doylestown, around 60 kilometers (40 miles) north of Philadelphia where an armed man fitting his description reportedly tried to steal the keys to a car, opening fire several times before vanishing into a wooded area.

Stone is suspected of shooting dead ex-wife Nicole Hill, 33, her grandmother, sister, sister's husband and 14-year-old daughter, as well as wounding Hill's 17-year-old nephew on Monday.

Hill was shot dead in her apartment in Lower Salford in the middle of the night in front of her two young daughters. The couple was apparently locked in a custody battle.

On Monday police SWAT teams searched in vain in Pennsburg, around 75 kilometers northwest of Philadelphia, where Stone comes from, and where he handed his daughters to a neighbor after the shooting.

Schools were closed in the area where the manhunt was taking place and residents were advised to stay at home with their doors locked.

Stone served more than eight years in the US Marine Corps.