Katherine Russell Tsarnaev enjoys fast food lunch with her daughter and a friend at Chipotle

Katherine Russell Tsarnaev, widow of Boston bombing suspect Tamerlan Tsarnaev, enjoyed a fast food lunch with her daughter on Sunday as federal officials continue to investigate whether she had any involvement in the deadly terrorist attacks.

Katherine Russell Tsarnaev, 24, laughed and chatted with a friend at a branch of the Mexican fast-food chain Chipotle along with her 3-year-old daughter, Zahara.

Tamerlan Tsarnaev’s widow appeared relaxed and carefree as she ordered at the counter before carrying a soda and bag of food to her car from the restaurant close to her home in Warwick, Rhode Island.

Katherine Russell Tsarnaev was likely trailed by undercover FBI agents in an unmarked car as officials remain suspicious about how much she knows relating to the planning and production of the pressure cooker bombs.

Her casual outing came as federal investigators revealed that they had discovered radical Islamist materials on her computer and the fact that she will not reveal what she spoke to her husband Tamerlan Tsarnaev about when they had a phone conversation on the night that his photo was released by the FBI.