As the search for U.S. college student Caleb Harris creeps toward the one month mark, police in Corpus Christi, Texas, have pieced together an extended timeline leading up to his mysterious disappearance. 

Harris, a 21-year-old student at Texas A&M, was last seen by his roommates and a friend during the early morning hours of March 4. The group were at their off-campus apartment playing video games, according to police.

They briefly went to the parking lot, where they played with a puppy belonging to the girlfriend of one of Harris' friends, before returning to the apartment. 

By 2:20 a.m., the last of Harris' roommates went to sleep. Harris informed them he was going to stay awake and place an UberEats order for his school lunch later that day, said police.

Twenty minutes later, Harris sent a Snapchat video to his sister appearing to show him walking the puppy through the apartment parking lot. Then, around 3 a.m., he sent a Snapchat photo of a bridge over a drainage ditch within a few hundred feet of the apartment entrance to a friend in San Antonio, according to police.

At 3:12 a.m., his cell phone was pinged by the nearest cell tower. Eight minutes later, Harris' UberEats order was delivered to his front door.

Around 11 a.m., Harris' roommates discovered the unopened order at their doorstep. His pickup truck was still in the parking lot, and his keys and wallet were located in the apartment. 

Police said the roommates became concerned about Harris' whereabouts, noting he was a "homebody and a creature of habit," and reported him missing.

Throughout their investigation, police said there was no evidence of a struggle or foul play found within the apartment or in the immediate area. 

The 31-year-old female UberEats driver has been ruled out as a suspect, as well as his roommates, friends and family, who have been "extremely cooperative," according to police. 

Investigators continue to scour through surveillance footage from over two dozen nearby cameras. Police said they are still analyzing Harris' laptop and other electronic data for any clues leading to his disappearance. 

The investigation remains ongoing.

Anyone with information is urged to contact the Corpus Christi Police Department at (361) 826-2840, Crime Stoppers a 888-TIPS, or the family's tip line at (361) 826-2950.