ISTANBUL

The Boulder attack suspect planned his assault for a year and specifically targeted demonstrators at a "pro-Israel" rally, according to FBI's criminal complaint on Sunday.

Mohamed Sabry Soliman, 45, told federal agents during a post-arrest interview that he had been planning the attack, in which at least eight people were injured, for a year and delayed it only until his daughter graduated, the court document showed.

"He stated that he wanted to kill all Zionist people and wished they were all dead," the document stated. "SOLIMAN stated he would do it (conduct an attack) again."

Soliman told investigators he "hated the Zionist group" and attacked because he needed to stop them from taking over "our land," referring to Palestine.

The suspect researched how to make Molotov cocktails on YouTube, purchased ingredients and constructed the explosive devices before traveling to Boulder, Colorado, according to the complaint.

- Premeditated targeting

According to the document, Soliman specifically targeted the pro-Israel gathering after learning about it through online searches. He arrived the area on Sunday five minutes before the scheduled time for the demonstration staged to raise awareness on hostages being held in Gaza and "waited for them."

"He traveled to Boulder, Colorado in his vehicle with the Molotov cocktails and threw two of the cocktails at individuals participating in a pro-Israel gathering," the FBI said.

Eight people suffered injuries in the attack, which federal authorities are investigating as terrorism.