Lawmakers belonging to Taiwan’s Democratic Progressive Party (DPP) called for an investigation on Tuesday into the alleged involvement of former legislative assistant and alleged spy Chen Wei-jen in the sending of packages of seeds from China to several countries.

According to DPP lawmaker Wang Ting-yu, “reliable sources” within Japan’s national security officials claim that the post office account connected to the delivery of the mysterious packages, the majority of which contained seeds, had ties to Chen.

On August 13th, the Taipei District Prosecutors’ Office indicted Chen and two other former legislative assistants on charges of violating the National Security Act by allegedly collecting classified materials and meeting minutes from the Legislative Yuan, the Ministry of Foreign Affairs, and the Mainland Affairs Council, and passing on details of government personnel to Chinese intelligence officials.

Chen is currently free on a NT$100,000 ($3,500) bail but cannot leave the country. Politicians including DPP lawmaker Chao Tien-lin argued that if officials can prove a connection between Chen and his alleged handler, working under the alias “Huang Guanlong,” his bail should be immediately rescinded.

The calls for an investigation come more than a month after thousands of unsolicited packages carrying seeds believed to be from China arrived in the mailboxes of Americans and others abroad, leading to a warning from U.S. agricultural officials not to plant them.

Some of these packages — falsely labeled as jewelry, toys, or electronic devices — had Chinese writing on them but are believed to have been shipped through Taiwan in an attempt to drive a wedge between Taipei and its western allies.

Federal officials from the Department of Agriculture (USDA) pledged to work with the Department of Homeland Security and local officials to prevent any more illegal seeds from entering the country.

“[We are] aware that people across the country have received unsolicited packages of seed from China in recent days,” the USDA said in a statement. “At this time, we don’t have any evidence indicating this is something other than a ‘brushing scam’ where people receive unsolicited items from a seller who then posts false customer reviews to boost sales.”

Residents of Tampa Bay in Florida also reported receiving unsolicited masks this month in what some believed to be a “brushing” scheme to boost sales. This technique involves third-party sellers creating fake orders in order to post positive reviews about themselves on online market places such as Amazon and eBay.

“The companies, usually foreign, third-party sellers that are sending the items are simply using your address that they discovered online,” notes the Better Business Bureau. “Their intention is to make it appear as though you wrote a glowing online review of their merchandise, and that you are a verified buyer of that merchandise.”

“They then post a fake, positive review to improve their products’ ratings, which means more sales for them,” its advice adds. “The payoff is highly profitable from their perspective.”