FORT WORTH, Texas -- The Iraq War veteran charged with gunning down a former Navy SEAL sniper and his friend has refused to meet with his family or court-appointed attorney, a Texas sheriff said Tuesday.

Eddie Ray Routh is charged with one count of capital murder and two counts of murder in the deaths of Chris Kyle, author of the bestselling book "American Sniper," and his friend Chad Littlefield at a shooting range Saturday. He's being held on $3 million bail and is on suicide watch.

Kyle, who had earned a reputation as one of the military's most lethal snipers while serving in Iraq, had a second book in the works, according to Sharyn Rosenblum, a spokeswoman for publisher William Morrow. No release date has been set for the new book, titled "American Gun: A History of the U.S. in Ten Firearms," and co-author by William Doyle.

Routh, 25, remained in his cell Tuesday instead of meeting with his lawyer or relatives, said Erath County Sheriff Tommy Bryant. Routh had demanded a cigarette in exchange for a meeting, but smoking isn't allowed in the jail, Bryant said.

The sheriff said he doesn't know which relatives came to visit Routh in the jail.

Routh was taken to a mental hospital twice in recent months and told authorities he suffers from post-traumatic stress disorder, according to police records.

Routh, a member of the Marines Corps Reserve, was taken to a mental hospital Sept. 2 after he threatened to kill his family and himself, according to police records in Lancaster, where Routh lives.

Police took Routh to Green Oaks Hospital for psychiatric care. Dallas police records show Routh was taken to the same mental hospital in mid-January after a woman called police and said she feared for Routh's safety.

Green Oaks will not release patient information, citing privacy laws. Most people brought by police to the hospital are required to stay at least 48 hours.

On Saturday, Routh allegedly shot Kyle and Littlefield multiple times at the sprawling Rough Creek Lodge in Glen Rose, where the three men had gone to use a gun range, authorities said.

Routh drove to his sister's house in Midlothian and told her he had killed two people and planned to drive to Oklahoma to evade Texas authorities, according to an affidavit. Routh also told his sister and brother-in-law he had "traded his soul for a new truck," according to the affidavit. His sister called police, and Routh was arrested near his Lancaster home driving Kyle's truck, authorities said.

Kyle and Littlefield apparently had been helping Routh work through PTSD, said Travis Cox, director of FITCO Cares, the non-profit that Kyle set up to give in-home fitness equipment to physically and emotionally wounded veterans.

Kyle, 38, left the Navy in 2009 after four tours of duty in Iraq. Littlefield, 35, was Kyle's friend, neighbour and "workout buddy," and also volunteered his time to work with veterans, Cox said.

Routh joined the Marines in 2006 and rose to the rank of corporal in 2010. His military specialty was small-arms technician, commonly known as an armourer. He had been stationed at Camp Lejeune, North Carolina, and served in Iraq from 2007-08 and in the Haiti disaster relief mission in 2010. He is now in the individual ready reserve.