An alert neighbor and an anonymous tipster provided the key information that helped police connect two suspects to the attempted murder of an 85-year-old woman and her caregiver.

Zachary T. Robinson, 19, and Cody Mikami, 21, were in police custody Thursday less than nine hours after the 3:30 a.m. beatings in Wai'alae Nui that left the victims in critical condition.

Yesterday, Robinson and Mikami were charged with one count of attempted murder in the first degree, two counts of attempted murder in the second degree, and one count of first-degree robbery, Maj. Clayton Kau of the Honolulu Police Department said.

Their bail was set at $1 million each. Both men were listed as having no local address. Both are expected to appear in District Court tomorrow.

The attack happened early Thursday morning on Halekoa Drive. Mary Lee Koskinen, 85, and her caregiver, 40-year-old Matthew Edmondson, were found severely beaten in their home. Police later said they had found dangerous drugs in the home and that the crime was not a random attack.

A court document released yesterday details what police found at the home and what led to the arrests.

Police had been alerted by an anonymous call about a disturbance, and arriving officers heard a woman yelling.

They went to the rear of the house and found the sliding glass door open. Officers saw Koskinen lying on her back, distraught and in great pain. Edmondson was lying in the living room, his face covered in blood — with a bloody brick and tire iron nearby.

Koskinen and Edmondson were taken to The Queen's Medical Center in critical condition shortly before 4 a.m.

The investigation continued as more officers arrived.

At about 7:35 a.m., a neighbor told officers she had seen an unidentified man standing in her garage and that he left when she asked what he was doing there. The woman told officers she could identify the man if she saw him again.

Officers combed the area, detailing descriptions of vehicles parked nearby in case the suspect had fled without his vehicle. Among them was a black 1999 Toyota pickup truck.

At about noon, an officer with the Waikíkí Crime Reduction Unit spotted the truck with two men in it near McCully Street and Kapi'olani Boulevard. The officer knew Mikami and saw that he was driving. The officer also said he knew that Mikami did not have a valid driver's license.

The truck turned in to a pay lot at McCully and Kapi'olani and parked in a handicapped stall. The officer approached the truck and recognized Robinson, whom he also knew, as the passenger.

The officer asked Mikami if he had a driver's license. When Mikami said no, he was arrested. A check revealed that Robinson had two outstanding warrants, and he was also arrested.

Later an anonymous tipster called a sergeant with the District 7 Crime Reduction Unit and said that a man he knew as "Zach" had approached him and asked him to take part in the Wai'alae Nui robbery. The tipster said he had heard that Zach had been arrested. The tipster later identified Robinson as the man he knew as Zach from a photo.

Officers then went back to the residence of the woman who had seen the unidentified man in her garage that morning. She also identified Robinson from a photo, the court document says.

At about 11 p.m. at the main police station, Robinson was placed under arrest on suspicion of attempted murder.

Meanwhile, Mikami was bound over on an outstanding warrant at a court hearing and ordered to be held at the O'ahu Community Correctional Center, police said yesterday.

Upon further investigation, he was arrested on suspicion of attempted murder at 11:10 a.m. yesterday, according to a police report.

Court records show Robinson has six previous arrests, but no convictions.

Three of his arrests are for contempt of court.

Robinson, who was born in Florida but has lived in Hawai'i since 2005, was last arrested Nov. 4 on first-degree burglary charges, after residents of a Waikíkí apartment reported someone broke into their unit while the three were sleeping and stole $570 in cash and a $2,500 laptop. He was arrested after an officer recognized him and another suspect on surveillance video leaving the apartment building, according to court documents.

Robinson was also a suspect in several other Waikíkí burglaries, the records show.

The Hawai'i Criminal Justice Data Center shows no criminal record for Mikami.