TEMPE, Ariz. -- Somewhere in Tempe's Salt River there could be another sign of missing ASU student Jack Culolias, 19.
On Tuesday the teen’s mother found a red Van’s shoe in the brush close to where Jack was last seen.
Alex Culolias is Jack's identical twin brother and he suspects the red shoe is Jack's.
"I've actually put my foot up there next to the shoe. It was a match to my foot too," said Alex.
The ASU freshman went missing from Cadillac Ranch, a bar in the Tempe Market Place.
Jack's mother said her son had a fake I.D.
Sigma Alpha Epsilon fraternity brothers said they all took a school bus to the bar Friday night.
Jack was pledging to get in to SAE last week.
The teen’s wallet and cell phone were found in the bar.
On Saturday morning the students noticed Jack didn’t make it home.
"I do not feel that he's in that lake and that he's here right. He could be just still lost," said Alex.
Search crews spent the day looking in the Salt River, which is within walking distance from Cadillac Ranch.
Crews searched under the water with a camera and through the brush.
"But as of now nothing has been located that says that Jack is in that area of the lake," said Tempe Police spokesperson Mike Pooley.
Surveillance video taken from the bar has so far been little use to investigators.
DNA was taken from Alex Tuesday night.
They will match it to DNA samples taken from the red shoe.
Pooley said he’s unsure when the samples will come back from the lab.
"I have seen him wearing those shoes. And those shoes weren't at his dorm. He was probably wearing those shoes that night," said Alex.
Jack's family is upset they found what could be a crucial piece of evidence.
The family questions why officers didn't search by the river right away.
"Yeah this is a logical place like the ASU Police didn't come out and look for him. This is just ridiculous you know? This is definitely ridiculous that we're doing their job for them," said Alex.
Pooley said the police department feels for the family and investigators are working hard to find Jack.
When asked about allegations about fraternity hazing, Pooley said the officers are looking into all leads.
The family has asked Tempe PD to get the FBI involved but so far agents aren’t working this case.
"I just want my twin back. I want him back to talk to him again," said Alex.