The D.C. Police Department's own Detective Tracy -- Frank Tracy, that is yesterday solved the caper of the missing helicopter equipment.

Poor communications and a misunderstanding were the main culprits in the disappearance, discovered on June 24, of more than $50,000 worth of helicopter parts, including two refurbished VO 435 Lycoming engines valued at $12,000 each.

The equipment was stored by Seabrook, Md., demolition contractor who removed it from the warehouse -- without the police department's knowledge -- before a scheduled demolition of the building at South Capitol and I streets SE, owned by the Exxon Corp. The warehouse had been used by the police department free of charge, for several years.

Police said the contractor, James White of Commercial Electric Inc., did not know the equipment belonged to the police department. It never had been labeled or tagged with police identification numbers.

According to police, White called the Exxon Corp. when he entered the building and found equipment and other items. Exxon officials told him to bring items marked "Exxon" to another company warehouse and to dispose of the other items as he saw fit.

Much of the department's equipment, police said, was surplus military hardware reconditioned during and after the Vietnam War by Lycoming, a Pennsylvania manufacturer. The inventory of police equipment stored at the warehouse included 15 turbochargers, three helicopter transmissions and other related aircraft parts in addition to the two engines.

The "theft" was discovered June 24 when officers went to the warehouse for an engine to replace another on one of the department's four helicopters. They found the warehouse door locks smashed and the equipment missing.

White heard news reports of the stolen equipment and realized that it was the same equipment he had removed, according to his attorney, Samuel F. Ianni.

Tracy said, "When White realized that the stuff belonged to the police . . . he called his attorney. But the attorney was out of town and White waited until the attorney came back."

The whole thing was a complete misunderstanding between Exxon and the police," Ianni said, "Exxon people didn't know what the stuff was. They thought the building had been abandoned." All the equipment will be returned.