MANILA - A powerful crime syndicate may have been involved in the killing of Korean businessman Ick-joo Jee at Camp Crame last year, Philippine National Police chief Director General Ronald dela Rosa said Tuesday.

Dela Rosa said the syndicate could make an attempt on the life of SPO3 Ricky Sta. Isabel, the primary suspect in Jee's killing, to prevent him from baring their nefarious activities.

This is why the PNP must retain its restrictive custody of Sta. Isabel instead of transferring him to Angeles City, Pampanga whose local court issued his warrant of arrest on Friday, the PNP chief added.

"Under threat itong tao na ito. Hindi ito pwedeng dyan lang sa kulungan ng Angeles City... Kailangan mag-manifest tayo doon na dito siya sa Crame makukulong," Dela Rosa said in an interview with radio DZMM.

"Malaking sindikato ito, malaking sindikato itong kanilang grupo. Joint operation nila ng PNP at NBI iyung pwedeng ma-implicate sa kaso, baka magka-interest sa kanya, iyung mga tinamaan, kung mayroon na silang mga previous cases na ganito."

(This person is under threat, he cannot be transferred to a jail in Angeles City. We need to manifest for him to be detained here at Crame. This is a big syndicate, their group is a big syndicate. The PNP and NBI has a joint operation against those who may be implicated in the case, and they may become interested in Sta. Isabel, those who may be tagged in previous cases like this.)

Sta. Isabel, together with several cops and a retired police official, are accused of abducting Jee from his Pampanga home last October 18 under the guise of a legitimate anti-drug operation.

Jee was brought to Camp Crame and allegedly strangled to death on the same day of his abduction, Dela Rosa said last week.

• READ: 'Tokhang-for-ransom': Timeline of South Korean businessman's abduction, killing

The PNP has filed a case against Sta. Isabel and his alleged cohorts, including his boss, anti-illegal drugs team leader Attorney Rafael Dumlao, and SPO4 Roy Villegas and PO2 Christopher Baldovino.

Authorities are still looking for Barangay 165, Caloocan chairman Gerardo Santiago, owner of the funeral parlor where Jee's remains were found; as well as an alias "Jerry", a supposed NBI asset who acts as Dumaloa's driver.

Dela Rosa said he suspects that Jee's murder was not the first crime of the suspects.

"Hindi pa talaga tayo nakakakuha ng ebidensya na ma-conclude nating dati nilang gawain iyan. Pero malaki ang posibilidad dahil wala e. Hustler na. Iyung bang sanay na sanay na, simple lang. Kung hindi ka ganoon ka-tibay pwede mo bang patayin sa loob ng kampo?"

(We have yet to obtain evidence to conclude that this has been their longtime modus operandi. But it is highly possible because they are already hustlers, highly practiced in what they do. If you were not that bold, would you have murdered someone inside the camp?)

The leader of the 165,000-strong PNP, however, urged the public to keep their trust in law enforcers.

"Sana po huwag kayong mawalan ng tiwala sa inyong PNP dahil iilan lag po silang gumagawa nito. Mas marami pa rin po kaming mga mababait... Please give us time, we will cleanse the ranks of PNP.

(I hope you don't lose trust in the PNP because only a few policemen commit these acts, there are more moral cops. Please give us time, we will cleanse the ranks of PNP.)