The unknown informant called the city of calbayog city police station to relay the information that the accused was going to catarman with a bag filled of marijuana, Acting on the said information, The police officer placed the accused under the surveillance. When the accused boarded a bus bound from catarman carrying a piece of luggage, The team leader instructed the chechpoint to stop the bus, as soon as the bus reached the checkpoint, the police officer opened the luggage of the accused and found marijuana inside, Is the warrantless seizure of the marijuana illegal? explain!