The police have traced the shop from where cycles used in the Gorakhpur serial blasts were bought and are quizzing two persons, including the shop owner, for clues.

"We have found some clues. The investigation is progressing in the right direction," Special Task Force Superintendent of Police P Amitabh Yash said on Thursday without divulging the details.

He said the investigators are questioning two persons, including the cycle shop owner.

Three crude bombs kept in tiffin boxes and tied to cycles went off at five minutes interval after 7 pm in a crowded shopping area of this temple town on Tuesday, injuring five persons.

The Uttar Pradesh government on Wednesday ruled out the use of the deadly RDX or any timer device in the low-intensity serial blasts in Gorakhpur that left six injured.