Police are investigating possible links between a bomb threat Tuesday morning against Metz Bakery and the explosion Wednesday evening that injured the son of a Metz employee.

Eleven-year-old Adam Cook, the son of Howard and Marian Cook, remained in critical condition at University Hospital on Friday morning after a pipe bomb attached to his father's Toyota Landcruiser exploded while Adam sat in the idling car waiting for his father, who had gone into the house at 5740 S. 660 West in Murray.The bakery received a call at about 8:30 a.m. Tuesday from someone who said a bomb had been planted in one of the company's trucks. The bomb that injured the Cook youth exploded about 9:20 p.m. Wednesday, throwing Adam from the vehicle and sending a blast that shattered windows in nearby houses and attracted a swarm of residents from blocks away to see what had happened.

The entire block was evacuated and cordoned off until about noon the following day while Federal Alcohol, Tobacco and Firearms investigators and Murray and county officers had searched the entire area for evidence. The bombed vehicle was towed to a secure storage area shortly after noon Thursday for further examination, said John Minichino, ATF agent in charge for Utah.

Minichino said a bomb expert will be brought in from San Francisco to examine the vehicle and fragments of the pipe bomb. It will likely be several days before investigators have a clear idea of the bomb's construction. Witnesses reported hearing Adam honk the car's horn just before the bomb went off, but Minichino said he did not know whether the horn had triggered the explosive.