A man serving a prison term for a drug offense is to be prosecuted again for using an encrypted message to manipulate a witness in his trial, the Supreme Prosecutors’ Office said on Thursday.

According to the prosecution, the man sent an encrypted message to a fellow inmate -- who is serving a sentence for an unrelated drug offense -- with directions for giving false testimony.

The man who gave the false testimony was also indicted, the prosecution said.

According to the officials, the man who sent the message was convicted of possessing methamphetamine last year but pleaded guilty.

He allegedly asked his friend, who was already in jail over a separate drug crime, for the favor. The two met while living in the U.S., the prosecutors said.

The officials said the suspect substituted numbers for letters: A for 1, B for 2, C for 3 and so on.

“You like math question right? Solve this,” he wrote.

“20.8.5+16.9.7.19-6.15.21.14.4-19.8.9.20.-9.14+20.8.5-16.1.4... Got the answer?”

The encrypted message informed the man’s friend that police had found drugs in his home. The suspect also said when prosecutors called him as a witness, he should claim he “only smoked bud (marijuana) but never used ice (methamphetamine).”

Prosecutors said the suspect was trying to claim that the drugs belonged to a third party.

The attempt failed as the prosecution seized the witness’ cellphone and decoded the message found on it.

The prosecution also found a psychotropic drug passed along by the witness’ cellmate and filed a charge against the two for violating the drug law.

By Suk Gee-hyun

(monicasuk@heraldcorp.com)