AUSTIN (KXAN) — Austin police confirm there were two rock throwing incidents Sunday morning on Interstate 35. Last week, police said they know of 54 reported rock throwing cases since the incidents began in the summer of 2014.

The first case took place at 2:52 a.m. in the 6300 block of N. I-35 northbound, just south of La Posada Drive.

At 9:03 a.m., another rock throwing case was reported in the 1600 block of S. I-35 southbound near Woodland Avenue.

Ed Scruggs, a newly-appointed public safety commissioner, said he’s convinced police will be able to catch the suspects when motorists see something, notices it and tells authorities immediately. “Some of these happen in the morning, some at night. And there are people around these cars. I think if people are paying attention we’ll catch them.”

When police started investigating the rock throwing cases, investigators thought the rocks were being thrown off overpasses and installed cameras along I-35 in downtown Austin to catch suspects in the act. In February, authorities said the rocks were being thrown from vehicles on the interstate driving the opposite direction.

On Mar. 7, police said the rock throwing incidents were not exclusive to I-35, naming Ben White Boulevard and U.S. Highway 290 as roadways where the incidents have also been reported.

The first reported incident was on June 14, 2014.