Police have arrested a 56-year-old Lawrence man for a robbery early Saturday morning at a convenience store near 23rd and Iowa streets.Charles E. Smith, 1200 N.Y., Apt. C, was booked into jail Sunday for aggravated robbery. Police identified him with help of surveillance video taken in a robbery between 1:45 a.m. and 1:50 a.m. Saturday at Presto, 2330 Iowa. According to a report, the suspect came into the store and demanded money from a 26-year-old clerk. The clerk told police the man didn’t display a weapon but kept his hand in his pocket. Kwik Shop, 1846 Mass., was robbed Nov. 16 by a man who kept his hand in his pocket but did not display a weapon, according to a police report. Robberies also have been reported in the past two weeks at Diane’s Liquor, 1806 Mass., and 23rd Street Liquor, 945 E. 23rd St.”The Lawrence Police Department is investigating the possibility that this robbery could be related to previous incidents,” police spokeswoman Kim Murphree said.-contributed by Eric Weslander.