Story highlights Martinez's partner was injured in the mysterious incident

They were found in a culvert after responding to a call

(CNN) The funeral Mass for Border Patrol agent Rogelio Martinez, whose death from injuries suffered last week in southwest Texas is puzzling investigators, was filled Saturday with family members, coworkers and other mourners.

Federal officials are examining the mysterious incident that left Martinez, 36, dead and his partner battered and unable to remember what happened.

US Attorney General Jeff Sessions and other law enforcement officials were scheduled to attend the private service at the Our Lady of Guadalupe Catholic Church in El Paso, Texas.

The city's iconic landmark Star on the Mountain -- a man-made illuminated star on the side of the Franklin Mountains --- will be lit over the weekend in honor of Martinez, CNN affiliate KFOX reported.

"Roger, our beloved friend, son, father and dedicated agent. We will miss you dearly. Tonight we light up the star in your honor. We love you, our hero," a certificate about the lightning of the star read.

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