Police are looking for a man in his 20s who took two diamond rings last night from a Waikiki jewelry store.

The man approached a clerk at Royal Hawaiian Gems, 2365 Kalakaua Ave., at 10 p.m. and asked her to show him two rings.

The clerk said he grabbed them from her hand and ran. A 19-year-old man who witnessed the heist and the store's security guard chased the robber, who fended them off by pointing a handgun at each pursuer.

The man is described as 5 feet 8 inches to 5 feet 10 inches tall, with a slim build, black hair and a dark complexion. He was wearing dark pants and a sweatshirt or windbreaker.

Moped rider hurt in barrier collision

A 42-year-old man was in guarded condition today at The Queen's Medical Center after his moped collided with a concrete median barrier on University Avenue.

The accident happened at 12:15 a.m. near the Coyne Street intersection. The rider, operating a 2001 Sundiro, lost control of the moped while traveling south on University and struck the barrier, police said.

Head injury blamed in Round Top death

The 61-year-old man whose body was found Monday morning along Round Top Drive was killed by a head injury, according to the autopsy performed by the Office of the Medical Examiner.

Forensic examination of Taaviliga Panapa's remains also turned up evidence of neck compression, said Susan Siu, head investigator. The examination hasn't produced a time of death, Siu said, but there was no evidence that the body had lain there for long.

The body of Panapa, who had no known local address, was found in the brush off Round Top, near the five-mile marker.

Teen arrested in Pearlridge robbery

One of two teenagers suspected in the robbery of a man waiting at a bus stop near Pearlridge Shopping Center was arrested today.

The first of two juvenile males approached the victim at the corner of Ka'onohi Street and Kamehameha Highway at 1:10 a.m. and demanded his necklace. The victim told police that when he refused, the suspect punched him in the face and took the jewelry.

The second suspect allegedly held the victim from behind in a headlock, took the wallet from the victim's pocket, removed cash and then tossed the wallet to the ground.

HPD announces promotions of 7

The Honolulu Police Department promoted five police officers and two civilian employees at a ceremony held today at police headquarters.

Capt. Douglas Miller has been promoted to major and assigned to the Legislative Liaison Office. Capt. Raymond Ancheta will take over Miller's past post as second in command of the Specialized Services Division.

Other promotions:

• Lt. Evan Ching, formerly of the Criminal Investigation Division (CID), is now a captain and will head the receiving desk at the Kapolei station.

• Sgt. Britt Nishijo and Officer Alan Togami have been promoted to lieutenant and detective, respectively, and are assigned to CID.

• Officer Robert Natividad's new rank is Metropolitan Police Officer II. He is assigned to District 6 (Waikiki).