Ninth-grader wanted in connection with grandmother's death detained trying to enter Canada Logan Mott, 15, is a "person of interest" in his grandmother's death.

 -- An "armed and dangerous" Florida teen reported missing earlier this week and wanted in connection with the death of his grandmother was detained Friday night by U.S. Customs and Border Patrol trying to enter Canada near Buffalo, New York, the Jacksonville Sheriff's Office announced Friday night.

Law enforcement officials named Logan Mott, 15, a "person of interest" in the death of his grandmother, Kristina French, 53, after police found on Friday afternoon what they believe is the body of French in a shallow grave in the backyard of her son Eric Mott's home in Neptune Beach, where the younger Mott also lives.

Officers with the U.S. Customs and Border Protection encountered Logan Mott driving a 2015 Dodge Dart around 7 p.m. Friday at the Peace Bridge near the center of downtown Buffalo after he made a wrong turn onto the bridge. The officers took Logan Mott into custody "without incident" after a primary inspection revealed he was the subject of a warrant for grand theft auto out of Florida, according to CBP public affairs liaison Aaron Bowker.

Upon confirming the warrant with Florida's Neptune Beach Police Department, the officers were advised that Logan Mott was also the "person of interest" in a murder investigation in Jacksonville. Mott was subsequently detained and is currently being held by the Buffalo Police Department on the grand theft auto warrant, Bowker said. He has not been charged in the death of his grandmother. It is unclear when he will return to Florida or if he has retained a lawyer.

Under a typical extradition process, the teen would appear before a Buffalo judge and either ask for a hearing on the validity of the warrant or waive the hearing, the Buffalo News reported. Officials in Florida would have 30 days to pick him up, once he was cleared to be extradited.

According to the Jacksonville Sheriff's Office, Mott had cut his hair short in an attempt to alter his appearance.

Following her son's capture, Carrie Campbell-Mott said in a statement to ABC News: "We are relieved he is safe and in custody and we just ask for everyone to give us time to sort out what happened. That no matter what, Logan is our child and we love him and are standing by him to help in any way. We want to find out what happened to Kristina and we need time for that to happen."

Both the teen and his grandmother had been reported missing since Wednesday, when Eric Mott returned home from vacation to find his son and mother both missing, and their home ransacked, police said.

The father, a corrections officer with the Jacksonville Sheriff's Office, also said several guns were missing from the home, ABC affiliate WJXX reported.

Police found signs of foul play, and French's silver Dodge Dart was missing, which led to Logan Mott also being wanted on an auto theft charge.

The body found in the shallow grave matches French's description, police said, but they are awaiting results from the autopsy before formally confirming it is her.

The Jacksonsville Sheriff's Office said Friday they had surveillance footage of someone matching Logan Mott's description, and they warned in a tweet, "he is considered armed and dangerous."

A police spokesperson stopped short of describing Logan Mott as a suspect, saying at a press conference Friday, "We need to talk to him about what happened in the house."

ABC News' Alexandra Faul and Morgan Winsor contributed to this report.