check in
check-in
To sign your name (as at a hotel or convention). To register at a hotel or motel. The adjective form check-in derives from this idiom.
The last guests to reach the hotel checked in at 12 o'clock.
Courtney arrived in town at mid-day and promptly checked in at the Plaza Hotel. The hotel permitted an early check-in time.
There were dozens of people at the airline counters waiting to check their bags in for their flights.
To arrive.
The friends we had invited did not check in until Saturday.
To receive (something) back and make a record of it.
The coach checked in the football uniforms at the end of the school year.
The students put their books on the library desk, and the librarian checked them in.
look into
check into
To find out the facts about; examine; study; inspect; to investigate; to examine carefully.
The mayor felt he should look into the decrease of income from parking meters.
Mr. Jones said he was looking into the possibility of buying a house.
The police are looking into the matter of the stolen computers.
The congressional committee will check into the financial dealings of the government contractor.