Prospects for a Senate trial of Philippine Vice President Sara Duterte were thrown into doubt late Tuesday, after the Senate voted to return the articles of impeachment to the House to ensure they aren’t in breach of the constitution.

Philippine senators have set themselves as an impeachment court for the trial of Vice President Sara Duterte over corruption and other criminal allegations but they voted to send the raft of complaints back to the House of Representatives due to legal questions.

Senate President Chiz Escudero wrote to Speaker Martin Romualdez about the cancellation of the presentation of the articles of impeachment