Thirteen Camp Pendleton, California, Marines arrested in July for alleged involvement with human smuggling at the U.S. and Mexico border have been charged, the Marine Corps has confirmed.

Charge sheets obtained on Thursday upon request by Marine Corps Times show allegations ranging from the theft of smoke grenades, obstruction of justice, distribution of drugs and the tampering with cellphones to protect Marines under investigation.

Only nine of the 13 Marines charged have been accused of conspiring or aiding in the smuggling of undocumented or illegal immigrants, and it is unknown how the charges for the other four Marines relate to the human smuggling investigation.

One lance corporal, with 1st Battalion, 1st Marines, was stopped by Border Patrol agents July 10, and has been charged with several offenses including the unregistered possession of a 9 mm Sig Sauer pistol on base and transporting unauthorized immigrants within the U.S. to help them avoid deportation, charge sheets show.

Another lance corporal, with 5th Marines, was charged with allegations related to the theft of four smoke grenades, one parachute flair and 20 rounds of blank 5.56 mm rounds, charge sheets show. That Marine was also alleged to have failed to report a violation of the Uniform Code of Military Justice, and was accused of conspiring to transport illegal immigrants.

The alleged theft of the military property occurred between May 1 and July 24, according to the charge sheet.

Twelve of the Marines charged were assigned to 1st Battalion, 5th Marines, and one was with 1st Battalion, 1st Marines.

The Naval Criminal Investigative Service conducted a mass arrest of 16 Marines during a battalion formation July 25. Thirteen Marines, 10 of them arrested during that battalion formation, were later charged for various involvement in the larger human smuggling probe.

The mass arrest followed the July 3 arrest by Border Patrol agents of two Marines, Lance Cpl. Byron Darnell Law II and Lance Cpl. David Javier Salazar-Quintero, near the U.S.-Mexico border.

Marine officials said the July 25 mass arrest stemmed from information gleaned from a previous investigation. It is unknown at this time if Law and Salazar-Quintero’s arrest was the domino that led to the arrests of the other Marines within 1st Battalion, 5th Marines.

Some Marines were charged with obstruction of justice, charge sheets now show.

One lance corporal allegedly destroyed the cellphone of another Marine involved in the human smuggling operation, while another tampered with the cellphone of two other Marines involved.

A corporal with 5th Marines, so far the highest ranking Marine involved, was alleged to transport a cellphone on or about July 18 from the barracks room of a Marine involved to a lance corporal “in order to obstruct the due administration of justice,” the charge sheet reads.

A lance corporal also was charged with the alleged distribution of LSD and cocaine. While the 13 charge sheets are related to investigation of human smuggling, the lance corporal alleged to have distributed the drugs was not charged with aiding or conspiring in the smuggling of undocumented immigrants.

It is unknown at this time how the Marine’s alleged cocaine and LSD charges are related to the human smuggling investigation.

The Marine is alleged to have distributed the drugs between March 1 and July 25, the charge sheet details.

Maj. Kendra Motz, a spokeswoman for the 1st Marine Division, previously told Marine Corps Times that all the charges at this time are preferred and the Marines will face an Article 32 hearing at another date.

During that hearing a preliminary hearing officer will determine whether the Marines will face a court-martial and what charges will may go forward, if any.

The Corps previously said that none of the Marines questioned or detained Thursday have been supporting military operations at the U.S.-Mexico border.

Overseas operations reporter Shawn Snow contributed to this report.