 Rojek of the FBI said the gunman's family was cooperating with the investigation. Law enforcement officials found materials for two explosive devices in Crook's car and believe they may have found a third at his residence, according to a person with knowledge of the investigation. Yesterday, a clue emerged as to how Mr. Crook's may have trained. And everybody's wondering now, how did he get up on the roof? One policeman went there after he was told, but the guy retreated because he did not have a weapon. All right. Why? Why did he not have a weapon?