She failed the second-round of lie detector test conducted by the National Bureau of Investigation (NBI) regarding the November 7 brutal slaying of veteran actress Nida Blanca, and now Elena dela Paz, the actress' trusted aide of 42 years, has offered to testify against the possible brains of the murder.

"After failing the two sets of (polygraph) examinations, she (Dela Paz) finally gave in and vowed to testify against the possible mastermind behind the murder of Ms. Blanca," an NBI source, asking anonymity, said.

The source added that Dela Paz, who was Blanca's personal secretary, was expected to provide key information on the identity of Blanca's slay mastermind.

The NBI is also pursuing a lead involving Blanca's close friend, who is also a show biz personality and belongs to a prominent political clan, the source said. The possible witness, who was earlier tagged as among the last individuals who were with Blanca in the hours before her murder, may appear at the NBI by next week.

The source added that this witness is one of Blanca's most trusted business partners in a casino-financing scheme. The slain actress would reportedly not act on any matters concerning money without first consulting this person's advice. Blanca also wanted this person to be around whenever money or other important business discussions were to take place.

The source said the NBI is expecting a breakthrough in its investigation with Dela Paz's cooperation.

Dela Paz and Blanca's husband, Rod Strunk, who were summoned by the NBI this week gave statements that were riddled with 'inconsistencies', the source said.

The NBI Director, Reynaldo Wycoco, said close friends and relatives of Blanca, such as Dela Paz and Strunk, may place themselves in a lot of trouble if they try to hamper the investigation.

He said Dela Paz has a lot of things to explain, adding that she seems to know a lot that she hid them from the investigators. He added that she may also know the identity of the killers and the mastermind.

Another close friend of Blanca, Candelaria Tantoco, has been reluctant to help in the investigation, the source said. The source added that the NBI will summon Tantoco, who had been friends with Blanca for 30 years, soon.