MEXICO CITY (Reuters) - Mexico’s elite Tecnologico de Monterrey university said on Friday that structural shortcomings contributed to the collapse of walkways on its Mexico City campus in an earthquake last month, killing five college students.

Rashid Abella Yunes, the school’s vice-president for the Mexico City region, told Reuters that examinations showed two sets of pedestrian bridges stretching between three buildings were too weak to withstand the Sept. 19 quake that toppled dozens of buildings and killed nearly 230 people in the capital.

“The supports that were supporting the bridges were just 15 centimeters, which to the judgment of experts could have been larger,” he said. “The buildings made the bridges lose support, and they fell.”

Abella added that the university was leaving to Mexico City prosecutors the task of determining if any of the architects, contractors or inspectors that it hired between 1991 and 1998 to build the bridges could be held responsible.

None of the professionals that Abella said worked on the bridges were immediately reachable for comment.

Construction and safety documents published last month by the Tlalpan district, where the campus is located, included an August 2017 structural safety certificate.

Abella also said that Mexico City’s construction regulations do not specify the size that bridge supports need to be in order be structurally sound.

The university, renowned for its engineering program, attributed its findings to Mexico City-based engineering firm Garcia Jarque Ingenieros, which it hired to investigate the collapse.

A group of nearly 100 alumni have been pressing the school to explain how the bridges were constructed.

“Of all of the doubts that we’ve had, none are resolved,” said Carlos Brito, a 2010 graduate.

Family members of two students who died at the site said their children were crushed by falling bridges as they raced out of the ground-floor cafeteria beneath.

Juan Carlos Alvarez Blanco said his son, 19-year-old engineering student Juan Carlos, decided to stay on campus for lunch and died attempting to exit the cafeteria.

“We want facts,” he said last week. “Along with the other four families, we are very, very devastated.”

A relative of another student who died, who asked to not be named, said the young man, who studied engineering, had also been in the cafeteria.

Both family members declined to provide further comment on Friday.