Dombroski went missing after playing in the Ariel Re International 7s in Bermuda on Saturday and later spending the evening at a bar called The Dog House.
The 19-year-old is described as 6-foot tall white male who has blonde hair.
Family members, including his parents and two brothers, have reportedly flown out to the island to assist with the search as authorities become increasingly concerned about his whereabouts.
"Members of the Archmere community will gather at the end of the school day to pray for the Dombroski Family, as we journey together with them in the days ahead", said Archmere Academy in a statement Monday.
The tournament reportedly was offering a $1,000 reward for information on Dombroski's location, according to NBC Philadelphia. He is still missing and there is concern for his wellbeing.
They are asking anyone with information to contact the police at 295-0011.
Acting Assistant Commissioner James Howard of the Bermuda Police Services declined to provide certain details, including how authorities believe he may have died during a visit to the British Island territory.