UPDATED 09/26/12 – 10:07 p.m.

EVANSTON, Ill. (CBS) — Family and friends are now offering a $25,000 reward as they intensify the search for Northwestern University student Harsha Maddula, who has been missing since the weekend.

As CBS 2’s Dana Kozlov reports, police spent the day Wednesday searching for Maddula, 18, in the area near Wilmette Harbor in Lake Michigan, at Sheridan Road and Michigan Avenue in Wilmette, about two miles north of the PARC dorm in Evanston where Maddula lived.

Also, Wednesday, a $25,000 reward was being offered for anybody with information about Maddula’s whereabouts. The 18-year-old sophomore is a pre-med engineering student who has been missing since early Saturday.

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Northwestern expanded the search to include Wilmette Harbor after police were able to trace Maddula’s last cell phone call to that location. Divers and Coast Guard boats were in the water searching for the boy throughout the day, but ended their search of the water after darkness fell.

However, University spokesman Alan Cubbage said police have not found any of Madulla’s personal belongings, including his cell phone.

Meanwhile, a university police officer looked in window wells near Maddula’s dorm. Friends say he came to campus several days before the start of school to help freshmen move in.

Maddula disappeared after leaving a party at a house in the 2000 block of Ridge Avenue in Evanston, west of the main Northwestern campus, around 12:30 a.m. Saturday. His family is concerned because he was recently diagnosed as diabetic.

He sent a text message a short time later indicating that he was returning to his room, but Cubbage said that there is no sign of the student on the dorm’s security cameras or keycard logs.

Sources who saw Maddula at the party told the Daily Northwestern that he was coherent, and was not obviously intoxicated or stumbling.

On Wednesday morning, Maddula’s parents wept as they spoke at a news conference on the Northwestern campus.

“We cannot control our emotions anymore, because we don’t know whether he’s alive or not,” said Harsha’s father, Prasad Maddula.

While Maddula’s family members are fearing for the worst, they are not giving up hope. They want more students to join in the search.

“More students, please come forward and search for Harsha,” Prasad Maddula said.

Meanwhile, volunteers are helping search for Maddula, even though they have never met him.

Prasad Sastla of Glenview, and Kalyna Anandula, were out searching for clothes, a cell phone or other identifying items Wednesday morning.

“We’ve been sending community alerts to basically all the Indian community,” Anandula said.

And as more students arrive on campus for classes to begin on Thursday, the number of volunteers grows.

“It’s just unfathomable to imagine, you know, such a normal guy. He’s not a high-risk guy. He’s not a high-risk guy,” said Northwestern freshman Allyson Fion.

“We just both empathize with the family and understand how difficult this is,” added Northwestern junior Nikhil Bhagwat.

Maddula’s aunt, Surekha Maddula, said the family is just trying to get through each day.

“It’s been a struggle, but you know, we have a large, close-knit family, and we’re all sticking together, and we just have to stay strong,” she said.

Maddula’s picture is on flyers plastered all over campus, and his family also called upon victims’ advocate Andrew Holmes to lend a hand in the search.

Holmes looked through dumpsters outside the house and found bags filled with beer cans and empty bottles of hard liquor.

Family and friends emphasize that Maddula’s health may be in danger.

“The primary focus right now is to find him and make sure he’s healthy,” said family friend Chai Medicherla. “Yes, he is diabetic, so the longer he’s away from his medication and care, you know, it just builds up; compounds.”

Maddula is described as a straight-A student who would never run off without notifying someone.

Surekah said she fears that he is comatose on a floor somewhere.

Maddula grew up in New Hyde Park, N.Y., on Long Island. Neighbor Sabrina Mahboob tells WCBS-TV, New York, that her husband spoke to Maddula’s parents hours ago.

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The neighbors in New Hyde Park are all on edge praying for a safe return.

“I have known him since he was 6 or 7,” Mahboob said. “He is a great kid a wonderful kid.”

The statewide Terrorism and Intelligence Center, as well as the FBI, are now involved in the search, helping Northwestern University police.

Although early reports indicated that Maddula is 5 feet 4 inches tall and weighs 135 pounds, the flyer distributed by the family indicates that he is 5 feet 8 inches in height and weighs 149 pounds. He has black hair, and was last seen wearing a gray sweater.

Anyone with information that could help lead police to the missing student is urged to call Northwestern Police at (847) 491-3456.

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