The managing director of Halotel, a Tanzania-based subsidiary of Vietnam’s military-run telecom giant Viettel, has been freed by a court in the East African country after he was found not guilty of charges including fraud and economic sabotage.

The Vietnamese company confirmed the release of Halotel executive, Le Van Dai, in a statement on Friday.

Dai was among those tried by a court that convened on Wednesday in the Tanzanian city of Dar es Salaam for their alleged involvement in a telecom fraud case.

A group of foreigners in Tanzania had previously been caught illegally keeping some 300,000 unregistered SIM cards, including those of Halotel, which are believed to have been used to evade rates payable for international messages.

Judges on Wednesday ruled that Dai and Halotel had not violated Tanzania’s criminal law and let him go free with only an administrative penalty for shortcomings in Halotel’s SIM management procedures that had allowed room for exploitations.

Dai has returned to work as top Halotel executive following the court ruling, according to Viettel’s statement.

The managing director of local telecom company Zantel, Sherif El Barbary, who had been accused of similar violations in the same case, was also freed by the court for the same reason.

Dai and Barbary, an Egyptian national, were arraigned on June 6 along with four others – two Chinese and two Tanzanian nationals – on accusations of conspiracy, fraud and tax evasion which have purportedly caused the government losses of about US$530,000, according to news website The EastAfrican.

In a statement made after the arraignment, Viettel said Halotel never directly sold any of the illicit SIMs, and that the subsidiary had nothing to do with any of the illegal actions taken by the foreigners charged in the same case.

Halotel, launched in October 2015, has been regarded by the telecom authority of Tanzania as having one of the best management systems and sales protocols in the local market, the company said after Wednesday’s ruling.

However, in light of recent events involving sophisticated tricks in the purchase of SIM cards for criminal intentions, Viettel said its Tanzania arm would continue to upgrade its distribution management system for better fraud prevention.