DETAINED Senator Leila M. de Lima has asked a Muntinlupa City trial court to dismiss one of her three drug-related charges after prosecutors allegedly failed to prove her guilt.

In a 59-page filing, the lawmaker, one of President Rodrigo R. Duterte’s staunchest critics, said the prosecution had “not only failed to provide evidence of guilt beyond reasonable doubt” but also “proved that this case has absolutely nothing to do with illegal drugs.”

She said prosecutors had failed to identify the specific drugs that she allegedly trafficked in the charge sheet. None of the 21 prosecution witnesses mentioned any drug names, she added.

“No shabu, marijuana, or any controlled precursor and essential chemical was presented in court and proven to be such by the prosecution,” according to a copy of Ms. De Lima’s pleading.

“In charging accused de Lima of a nonbailable offense, the prosecution merely relied on the general and dubious statements of inmates convicted of crimes involving moral turpitude, the very same convicts who denied involvement in the illegal drug trade, while conveniently failing to allege or prove any specific illegal drug involved,” she said.

Ms. De Lima is on trial for allegedly abetting the illegal drug trade in the country’s jails when she was still Justice secretary. She was accused of extorting millions of pesos from a drug lord that she allegedly used to finance her senatorial campaign in 2016.

She has been jailed at the Philippine National Police Custodial Center in Camp Crame since February 2017. Several witnesses against Ms. De Lima were drug convicts serving time at the national penitentiary in Muntinlupa City.

The European Union Parliament earlier adopted a resolution urging the Philippines to free Ms. De Lima and look at extrajudicial killings in Mr. Duterte’s anti-drug campaign.

“The facts are clear and they cannot be ignored: All of the country’s intelligence agencies never had a single report stating that accused de Lima was involved in any way in the trading of illegal drugs,” Ms. De Lima said. — Vann Marlo M. Villegas