Ivory kingpin Feisal Mohammed is a free man.
Judge Dora Chepkwony quashed his 20-year jail sentence, terming it unconstitutional. Feisal had also been fined Sh20 million.
Chepkwony said Feisal had already served enough time because he has been in prison since the time his trial began.
The judge said after interrogating the evidence adduced before the court, she found many gaps.
Chepkwony said the evidence was circumstantial.
Feisal had been charged alongside five other people who were acquitted.
A Mombasa court had sentenced Feisal in 2016 after he was found guilty of possessing Sh44 million ivory.
Principal magistrate Diana Mochache said considering the circumstantial evidence tabled in court, Feisal was guilty.
She also fined him and said he must serve as an example for those behind the poaching menace in the country.
Feisal was arrested by Interpol agents in Dar es Salaam, Tanzania, in December 2014.
The magistrate acquitted the other accused persons, saying they had been caught up in Feisal's dealings unknowingly.