The streak of violence began when a driver struck a person outside a Gaithersburg, Md., mosque on March 22 and fled the area, police said. Two days later, someone smashed a brick into a car outside a Germantown mosque, before leaving the scene.

Later that day, police say a driver intentionally rammed a Manassas, Va., grandmother as she stood on the street outside her home, before speeding off. Shamsa Begum, 66, died at the hospital the next day.

Authorities in Maryland and Virginia have now charged the same man in all three incidents: Muhammad Taha, 29, of Clarksburg, Md. But what remain a mystery are a motive and any links between the incidents.

“At this point, we don’t have a concrete motive,” said Officer Charles Sharp, a spokesman for Manassas City police. “We can’t rule anything out.”

Taha is facing charges of second-degree murder and hit and run involving death in connection with Begum’s death.

He also faces charges of attempted second-degree murder, first-degree assault and two counts of malicious destruction of property in connection with the Maryland incidents.

Police said they have no evidence the cases are linked to anti-Muslim bias, but they are still trying to figure out what motivated Taha.

Montgomery County police were called to the Islamic Center of Maryland mosque in the 19000 block of Woodfield Road in Gaithersburg on March 22 for the report of an injured person, police said. Police said the victim suffered serious injuries when he was struck by a driver, who left the scene. Surveillance footage captured part of the incident.

“To the best our knowledge, this individual is neither connected to our center . . . nor [do] we have any information about this individual or his motivations,” Nadeem Ahmad, chair of the center’s board of trustees, wrote in an email.

On March 24, officers responded to the Islamic Society of Germantown mosque in the 19000 block of Blunt Road in Germantown for a report of a suspicious situation, police said. Witnesses saw a vehicle circling the parking lot before the driver exited and used a brick to vandalize another vehicle in the lot, police said. The driver then struck another car while driving away from the scene.

Mosque officials did not respond to a request for comment.

Sometime later, Sharp said Taha drove to Begum’s home in the 9600 block of Cloverhill Road in Manassas and threw a brick or other item through a window. Sharp said Taha and Begum are related, but he declined to say how.

Begum left her home to investigate what happened, and witnesses told police Taha intentionally drove into her while she was in the middle of Cloverhill Road. Minutes later, Prince William County policeCounty police located him at a 7-Eleven nearby. He was charged with driving under the influence and possessing an open container.

Begum succumbed to her injuries the next day.

Her family members did not respond to requests for comment, but a nephew who created a GoFundMe page for Begum‘s family wrote on the page that her slaying was a “senseless and unprovoked crime.”

“Shamsa was a loving spouse, successfully raised 3 grown children, and was a doting grandmother to 3 young boys,” the nephew wrote. “She was the epitome of the American dream, having built a fruitful life in the U.S. through hard work and perseverance.”

Begum led a life of “unexpected challenges,” the page says, including immigrating to the United States from Pakistan and surviving a kidnapping attempt in Saudi Arabia. The nephew described her as a “warm and uplifting presence.”

She was planning her son’s wedding in the hours before she was killed, the nephew wrote. The GoFundMe campaign has raised over $26,000 for her surviving family members.

Less is known about Taha. Relatives and his attorney did not respond to requests for comment, and it is unclear whether he was employed.

Taha is being held without bond at the Prince William County jail. His next court appearance is scheduled for May 20 in Prince William County.

Clarence Williams and Dan Morse contributed to this report