(CNN) -- The Mexican military has arrested four more people connected to the killings of 15 people at a January house party in Ciudad Juarez, Mexico, bringing the total to seven suspects arrested and one killed, according to documents from the Mexican attorney general's office obtained by CNN.

Last Sunday the Mexican military, in connection with federal police, arrested Heriberto Martinez, a self-proclaimed member of the Aztecas, a Juarez street gang that acts as the Juarez cartel's enforcers in the city. State prosecutors say Martinez committed at least four killings and acted as a lookout during the house party massacre in Villas de Salvarcar, a southern suburb of Juarez, in the early morning hours of January 31.

The house party slayings of 15 people, most of whom were students with no ties to organized crime, has sparked outrage across the country. The slayings are thought by officials to be the result of bad intelligence by the cartel and by the gang that carried out the killings.

Another one of the four arrested recently was Luis Alberto Camacho Ramos, alias "El Shoker" or "El Flaco," who according to documents obtained by CNN confessed to participating in the house party killings. Ramos, along with admitted drug cartel member Jesus Bustos Renteria, was arrested in the beginning of March, according to the documents.

The documents obtained Saturday, forwarded exclusively to CNN by someone close to the investigation, show that at least one of the four men recently arrested -- Alfredo Arias, alias "Arnold" -- was signaled out during testimony by Aldo Favio Hernandez Lozano, alias "El 18." Lozano was a municipal police officer arrested last month who state prosecutors say was a hit man in the January killings. During testimony, Lozano said it was Arias who originally called him to order the house party hit. Arias also supplied the weapons for the killings, Lozano said during testimony.

Arias had been sought in connection with a different killing. Six people, including 26-year-old U.S. Air Force Airman David Booher, died in a November 2009 shooting carried out at a strip club in Juarez, according to Juarez Mayor Jose Reyes Ferriz.

In a press release last week by the Chihuahua State Attorney General's Office, Arias was identified as the gunman in the strip-club shooting through surveillance video taken at the club.

Still photos included in the documents obtained by CNN show a man who resembles Arias, wearing a hat and hooded sweatshirt, removing a gun from his waist band and opening fire shortly after entering the club.

Arias was caught on March 16, while driving his son in the colony of Plutarco Elias Calles. In his possession, according to officials, were dozens of rounds of ammunition and at least 3 guns, including an assault rifle commonly known in Mexico as "un cuerno de chivo" or "goat's horn" because of the gun's banana shaped clip. It is the weapon of choice for drug cartel members in Juarez.

According to the press release, Arias was also the apparent leader of the drug cell "Los Linces," and it was that cell that ordered the killing on January 31 in southern Juarez.

Another man identified as the mastermind behind the killings -- Adrian Ramirez Armendariz, alias "El Rama" -- was killed by the Mexican military days after the house party killings.

Arias "was at one time in U.S. custody, but was later deported to Juarez," Reyes said. "It really underscores the fact that many of the criminals we have in Juarez were illegal aliens in the U.S. that have been deported from the U.S. into Juarez."

Reyes said in recent years as many as 100,000 Mexican nationals living illegally in the United States have been deported to Juarez, just across the border from El Paso, Texas.

"We did a study of the killings during an isolated period recently and cross-referenced to the date we have of deportation. We found that 10 percent of those killed in previous months from the time we made this study actually had been deported within the last two years from the U.S. to Juarez."

CNN could not immediately authenticate whether or not Arias was at one time in U.S. custody.

On Sunday, Reyes told CNN he was looking forward to meeting with Secretary of State Hillary Clinton when she visits Mexico this week. Department of Homeland Security Secretary Janet Napolitano also is scheduled to visit Mexico this week.

The announcement of the arrests comes on the same weekend a funeral was held in El Paso for two of the three people associated with the U.S. consulate in Juarez who were killed last week after they left a social gathering.

Reyes said last week that authorities believe those slayings were carried out by the Barrio Azteca drug gang. No motive has been revealed, and no arrests have been made.

About 200 U.S. federal, state and local authorities interviewed more than 100 Barrio Azteca members and associates in El Paso and southern New Mexico on Thursday, the U.S. Justice Department said.