A couple in Tiantai county, Zhejiang province, have been placed under criminal coercive measures on suspicion of extortion, local police said Tuesday.

Earlier media reports said the pair were poisoned and admitted to an intensive care unit after eating baby napa cabbage they had bought online. The couple later claimed that rat poison was detected in the cabbage.

Tiantai's public security bureau said it carried out traceability checks, on-site inspections, laboratory tests, and interviews, and that it had taken action against the couple, surnamed Chen and Yang.

The case remains under investigation.