Months After Student's Remains Were Found in Well, Authorities Discovered More of Him — but Still Don't Know How He Died

• The Corpus Christi Police Department said that a human rib was found in December 2024 at a water recycling plant, the same location where remains belonging to Caleb Harris were found months earlier
• The Nueces County Medical Examiner's Office announced the positive identification of the bone on March 28
• The medical examiner's office said the cause and manner of Harris' death remain undetermined

Authorities in Texas have confirmed that a human rib found last December belonged to Texas A&M student Caleb Harris, whose remains were found in a wastewater well months earlier.

The latest update into the tragic death of the college student came on Friday, March 28, when the Corpus Christi Police Department (CCPD) said a city employee at the Greenwood Water Recycling Plant found the bone on Dec. 2, 2024.

“The Greenwood Water Recycling Plant is the same location where the contents of the Perry Place lift station were transported to in June 2024, following the discovery of Caleb Harris's remains,” authorities continued.

According to authorities, the bone was discovered by subcontractors in a drying bed at the facility. It was taken by a CCPD officer and transported to the Nueces County Medical Examiner’s Office.  

The Nueces County Medical Examiner's Office announced the positive identification of the bone in an amendment obtained by PEOPLE on Friday, March 28.

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories.

As for why it turned up months later, a CCPD spokesperson said that it's possible the rib was overlooked among the human remains found last June, the Caller-Times reported. 

Based on interviews with family and friends and a review of surveillance footage, police previously said they were able to determine that Harris spent the evening of March 3 at his off-campus apartment on the 1900 block of Ennis Joslin Road with his roommates and a mutual friend. 

Around 2:44 a.m., on March 4, Harris shared a Snapchat video with his younger sister that showed him walking a puppy through what appears to be the complex's parking lot, according to police. Several minutes later, he shared a Snapchat photo with a friend of a small bridge within a few hundred feet of the entrance to his apartment complex.

Deputy Chief Billy Breedlove of the Corpus Christi Police Department told PEOPLE in July that they din't know how Harris ended up in the sewer system in the first place. While it was possible that Harris was "harmed and then was put there" — although they have no evidence of it — the investigator said it was also possible that an accidental fall into a manhole was to blame.

When Harris' autopsy report was released the following month, authorities said that at the time his remains were found, they were already in an "advanced state of decomposition and skeletonization."

“While no significant traumatic injuries are identified, the condition of the remains could have obscured subtle injuries and/or additional significant natural disease,” the medical examiners continued, noting that his toxicology analysis came back negative. 

Ultimately, the medical examiner wrote that the "exact details" leading up to his death remained unclear. "Hence, the cause and manner of death are classified as undetermined at this time. If additional information becomes available in the future, the cause of and manner of death can be amended, if needed," the official added.

The medical examiner’s office stated in its amendment shared on March 28 that the cause and manner of Harris’ death remain undetermined. 

PEOPLE contacted the CCPD for additional information on Monday, March 31.