TORONTO - A Canadian accused in a massive hack of Yahoo emails will have to stay in custody as he prepares to fight extradition to the United States.

Lawyers for Karim Baratov say the 22-year-old's bid to contest a judge's decision to deny him bail has been dismissed.

Baratov had argued Ontario Superior Court Justice Alan Whitten made a number of errors in principle when he found the young man was too much of a flight risk to be released on bail.

In his April ruling, Whitten also said Baratov's parents would not make suitable supervisors because they had not questioned his growing wealth or his business activities while he was living with them.

Baratov was arrested in March under the Extradition Act after U.S. authorities indicted him and three others -- two of them allegedly officers of Russia's Federal Security Service -- for computer hacking, economic espionage and other crimes.

His lawyer Amedeo DiCarlo says they will now focus their efforts on challenging the extradition order.