SPOKANE, Wash. -

Judge Annette Plese kept assault suspect Avondre Graham's bond set at $250,000 during the teen's initial appearance Monday afternoon.

The courtroom was standing room only when Graham made his appearance on charges that he robbed and assaulted a woman walking along the Centennial Trail south of Mission Park. The attack was thwarted by a passerby, Josh Gahl, who helped police track down Graham after the assault.

Graham reportedly confessed to Spokane police that he had assaulted the woman, who had to seek medical attention after the attack due to the beating she received at the hands of Graham.

The 17-year-old is suspected in a string of attacks on the Centennial Trail over the last six months. In addition to last Thursday's attack, he's also suspected to be behind an August 30 attack on a Gonzaga student while she was jogging in the same area; the May 3 murder of Sharlotte McGill, who was stabbed while walking her dog near Riverton and Magnolia, and the March 1 attack of Sherrie Wright, who was also walking her dog along Tuffy's Trail when she was assaulted and knocked unconscious near the spot where McGill was killed.

In each case, the attacker was described as a black male including the most recent attack where both Josh Gahl and the assault victim identified Graham as the suspect.

It appears Major Crimes detectives have considered Graham at least a person of interest for the attacks for quite some time, not only because of his bad eye but because he lives just across the street where two of the attacks occurred and reportedly back in February he threatened to kill his whole family.

With Judge Plese keeping Graham's bond set at $250,000, it gives detectives more time to investigate the McGill murder and firm up their case against him.

"While we have a huge chunk of it that perhaps it is Avondre, we are not at a point where we can charge him with murder yet . That's a very serious charge and obviously if we are going to charge somebody with that we have to have all of our ducks in a row and that's what we're doing," Spokane police spokesperson Officer Jennifer DeRuwe said.

That started last Thursday when detectives got a warrant to search Graham's apartment for things he may have stolen from McGill during her fatal stabbing in May. Spokane County Sheriff's deputies are helping with the case, taking advantage of low water conditions in the Spokane River to search for weapons in any of the attacks.

Detectives' efforts to investigate the McGill murder have been hampered, however, by the lead detective being tied up in court with Shellye Start's re-trial for murdering her husband, as well as the allegation by investigators that other potential suspects have been lying to them.

"I can tell you that people have not been completely honest with us. Detectives do believe there are people out there hiding information who may not be forthcoming with it," DeRuwe said.

The one person who is telling the truth is Graham who, according to court documents, readily admitted his involvement in last Thursday's attack.

Detectives will not confirm if Graham confessed to McGill's murder but do hope that now he's in custody people with knowledge of the murder will come forward and talk with investigators.

"We have a handful of different things that maybe there's a connection between Avondre Graham and the McGill homicide but we still have a lot more questions that need to be answered," DeRuwe said.

DeRuwe added no one wants to catch McGill's killer more than the Spokane Police Department does do but it will stay take more time. 

"As soon as we have more information, as soon as we can tie him to that murder 100-percent, we will. But I think it's important for the community to know that while it's on their radar, it's on ours as well," she said.

Crime Stoppers is now offering a $1,000 reward for information in the McGill murder case and the police department is trying to boost that amount.

While he will be tried as an adult for last Thursday's assault, Graham is being held in juvenile detention. His next court date is set for Sept. 27.