Who were the high-profile inmates involved in the bloody stabbing incident that killed one crime lord and left four others injured on Wednesday?
The bloody brawl in the New Bilibid Prison's (NBP) Building 14 allegedly started when an inmate called the attention of three Chinese inmates for using illegal drugs, Justice Secretary Vitaliano Aguirre said.
But previous events in the NBP would show that the inmates involved in the riot have had long-standing feuds that may be connected to the Bilibid drug trade.
Jaybee Sebastian, convicted for car theft and kidnap for ransom, became a household name after several inmates tagged him as the "most powerful" prisoner in the NBP due to his supposed close ties with former Justice secretary, and now senator Leila De Lima.
De Lima said Sebastian was a government asset after at least five gang commanders claimed that Sebastian asked them to sell narcotics to fund De Lima's senatorial campaign.
There were also insinuations romantically linking Sebastian to De Lima. De Lima vehemently denied the accusations, and claimed the administration resorted to "lies" to discredit her for being a staunch critic of the president.
Aguirre said Sebastian, who was in the NBP since April 3, 2009, initially agreed to spill the beans about alleged anomalies in the food budget for inmates, but "clammed up" after he was asked to also disclose details about the NBP drug ring.
He is known to head the "Presidio" side of the NBP, and is a rival of Herbert Colanggo who leads the Bilibid's "Carcel" side.
Tony Co, who died in the riot, was detained at the national penitentiary since January 22, 2012 for cases of carnapping and kidnap for ransom.
He was also accused of masterminding a grenade attack in the NBP in 2014 that killed an inmate and injured 19 others.
Two inmates testified that the 2014 attack was meant to target Jaybee Sebastian, known to be Co's top competitor in the illegal drug trade in the NBP.
Witnesses said Co plotted the attack after Sebastian ordered all inmates who have outstanding debts to Co not to pay up.
Tony Co was earlier identified by the National Bureau of Investigation as one of the men of Peter Co, another drug lord in the NBP.
In a raid in 2014, Co allegedly conspired with jail guards to conceal his luxurious lifestyle within the national penitentiary.
A "hidden room" was constructed inside his detention house in the NBP a few days before a raid to conceal a jacuzzi, a split-type aircon, and an exercise machine, among others.
Peter Co, a convicted drug lord, has been an NBP inmate since April 1, 2002.
Co, whose real name is Wu Tuan Yuan, was publicly named by President Duterte as part of a drug matrix involving widespread illegal drug operations in the Philippines. Co, according to the matrix, is in charge of "Triad Visayas."
He is part of the 'Bilibid 19' or the group of high-profile convicts who had been detained in the National Bureau of Investigation (NBI) headquarters last year following the discovery of several contraband items in their cells.
Many believed that he continued to conduct drug operations while in detention. Authorities discovered in his possesion material suspected to be shabu (methamphetamine hydrochloride), six guns, a storage area, a secret pathway, entertainment appliances, P1.4 million cash, and a sauna facility inside his cell during a raid in 2014.
Firearms recovered from Co's cell were registered under the names of a congressman, and other government officials.
Convicted drug lord Vicente Sy entered the NBP on December 14, 1999.
He is also a part of the 'Bilibid 19' as he used to be detained in a cell with two airconditioning units prior to the 2014 raid.
Clarence Dongail, a former police chief inspector, was convicted for the kidnapping and murder of a former Bacolod City barangay chairman and two maritime instructors, and is serving a 120-year jail term.
Among the five, Dongail is the lone non-member of "Sigue Sigue Commando" and is said to belong to another gang. Bureau of Corrections (BuCor) Director-General Rolando Asuncion bared that Sebastian and Dongail were not on good terms prior to the stabbing incident.
--- with a report from Ina Reformina