Detectives late Monday were investigating how four dry ice bombs -- two of which exploded -- were placed in restricted areas at Los Angeles International Airport.
A dry ice bomb exploded Monday about 8:30 p.m. in a section accessible only to employees near the gate of the Tom Bradley International Terminal, law enforcement authorities said.
Two similar devices were found in the area. All three were bottles with dry ice inside, according to LAX police.
The devices appeared to be outside the terminal near planes, according to television news footage.