Three days after his girlfriend's body was discovered wrapped in a camping tent and weighted down by a paint can in Lake Travis, Joe Carr was stopped trying to cross the Canadian border, according to the Travis County sheriff's office.

Carr was charged with tampering with evidence late Monday, and he is the main suspect in the death of 22-year-old Veronica Navarro, sheriff's spokesman Roger Wade said.

Deputies were en route to North Dakota to interview Carr, Wade said, and more charges are expected to be filed.

Officials believe Carr, who works for the Pedernales Fire Department, could have been alerted about the discovery of the body Wednesday by his colleagues, who assisted in recovering the remains near Pace Bend Park.

"We think he committed the crime, then when we found the body, he high-tailed it to Canada," Wade said.

Carr, 27, was on duty for 48 straight hours from July 4 to July 5 for the department, where he is a fire engine driver, according to Mark Warren, the department's assistant chief.

Warren said Carr was off duty on Wednesday and failed to show up for his next shift, on Sunday.

Navarro's family told investigators that she recently moved into Carr's Spicewood home, according to an arrest affidavit issued for Carr. Her cousin told investigators that Navarro was supposed to spend the weekend of June 24 with cousins in Austin but canceled because Carr had the day off and wanted to spend it with her, the affidavit said.

Navarro's cousin spoke to her the next day, when Navarro said she could not go out because she had to take care of Carr's son, the affidavit said. It also said the last contact anyone had with Navarro was through Facebook on June 27.

On Saturday, Wade said, investigators received word from Canadian law enforcement officials that Carr was attempting to enter their country by obtaining a tourist visa. Wade said it was not clear why Canadian officials contacted authorities here, because an alert had not been sent out about Carr.

A representative with Maryland-based Capitol Visa Services said Monday that a U.S. citizen is not required to obtain a tourist visa to visit Canada.

Detectives notified Canadian officials that Carr was a suspect in a homicide and that they were obtaining an arrest warrant, Wade said.

U.S. customs officials detained Carr until a warrant for tampering with evidence was issued, and he was taken to the Pembina County sheriff's office in North Dakota, where he is being held on $100,000 bail.

The affidavit said detectives searched Navarro and Carr's home Saturday and found several items that were connected to items found at the crime scene: paint cans with labels showing they were purchased on the same date and from the same location as the one found attached to Navarro's body, camping gear matching the tent that her body was wrapped in, and the type of trash bag discovered with Navarro's body.

Carr's Fire Department colleagues were surprised to learn about his arrest.

"We have not noticed any change in his attitude," Warren said. "He was a good firefighter and a good employee; that's why we are shocked."

He is still employed by the department, Warren said, but that is expected to change this week after Carr misses several shifts. A background check was ordered for Carr when he began working for the department in 2008, and Warren said Carr had a good work record.

Carr has a conviction in Williamson County for assaulting a family member in 2009 for which he received deferred adjudication, according to public records.

Detectives are asking anyone with information about this case to contact the sheriff's office at 854-9710 or Crime Stoppers at 472-8477.