[Updated at 1:33 p.m. ET] A team from the FBI is going to Lebanon to assist in the investigation, U.S. State Department spokesman Mark Toner said Monday.
[Posted at 9:13 a.m. ET] Lebanon's top intelligence officialÂ was going to be briefed about threats made by text message, a member of parliament told CNN on Monday.
The meeting was scheduled for Friday afternoon. Brig. Gen. But Wissam Al-Hassan never made it. He was killed Friday in a Beirut car bombing.
The alleged texts came from a Syrian phone number, parliament members from the opposition Future Movement party said. Four other Future Movement leaders all received the same message on the day they say al-Hassan was assassinated, Ahmad Fatfat, a Future Movement parliament member, told CNN on Monday.
Al-Hassan was a critic of Syrian President Bashar al-Assad's rule, and his death has led some to blame the attack on the Syrian government.
After al-Hassan's death, another chilling text message came through.
"Mabruk, the countdown has started. One of ten," the text message said.
Mabruk means congratulations in Arabic.
On Sunday, party members received a third threat, Fatfat said.