BAGHDAD, Iraq — The bomber seemed ready to die in any of several ways on Monday: In the trunk of his car was one bomb. Around his waist was a belt of explosives.
In all, one Iraqi investigator said, the man was wired to 50 or more pounds of pure explosive that he detonated at 8 a.m. in the parking lot of the U.N. compound, a month after a suicide bomber killed 22 people there.
The blast killed the bomber and an unarmed police officer getting ready to search his car, and wounded 19 others, many of them Iraqi police officers.
Officials here say it seems likely that the bomber had planned to slip into the fortified compound — but there is no evidence that he tried — to deliver the message that the United Nations remained a target in the continuing war.
"That makes sense, given the circumstances," said Lt. Col. George Krivo, an American military spokesman.
In Monday's bombing, as in the other attacks, Krivo said there was no firm evidence of who was behind it — loyalists of Saddam Hussein, al-Qaida operatives, or someone else. But he suggested that as American forces crack down on militants around the country, the military might be beginning to encounter "the worst of the worst."
"We're getting down to the most hardened, most difficult former regime loyalists and others who will stop at nothing to try to prevent the progress that is being made in the vast majority of the country," Krivo said.
On Monday morning, about 10 Iraqi policemen — from an unarmed unit that protects public buildings here — were searching cars entering a parking lot used mostly by Iraqis.
One of the officers said there were three cars waiting, including an old white Mercedes. Another officer, Mahmoud Mousa, 30, said a co-worker, whom he knew only as Ahmed, asked, "Should I check this one?"
Ahmed asked the Mercedes driver to open the hood and the trunk and step out of the car. As the driver reached down, the first guard, said, there was an enormous explosion and Ahmed was torn to pieces.
"This is my friend's flesh and his blood," Mousa said, holding up his spattered and shredded shirt, as he lay wounded at Al Kindi hospital.
The wounded officers said they believed that they themselves were the target to send a message to Iraqis not to work under American occupation forces.