LYNN – He won’t discuss his missing son’s whereabouts with police, but detectives are interested in Ernesto L. Gonzalez, Jr.’s public library computer use as they continue searching for 5-year-old Giovanni Gonzalez.Gonzalez, 36, used library computers and looked at books in the children’s room on several occasions over the last year, according to library workers.Theresa Hurley and her coworkers recognized the Brightwood Terrace resident as soon as they saw a flyer seeking the public’s assistance in finding Gonzalez’ son.”He was a quiet, well behaved patron,” Chief Library Nadine Michell said, adding, “The boy was never seen here.”Mitchell said a Lynn police detective asked library employees about Gonzalez’ reading and computer habits Tuesday morning. As of Tuesday afternoon, police had not applied for a search warrant in District Court to access additional information about Gonzalez.She said the library’s ability to provide detailed information on books Gonzalez checked out or information he was viewing online may be limited. She said checkout records for library material are erased as soon as the book, compact disc or video is returned.The library uses an anti-virus software called Centurion Guard that erases library computer memories.”Once the computer is shut down, that memory is gone. It’s like a needle in a haystack searching it,” Mitchell said.Mitchell thinks Gonzalez’s trips to the children’s room were aimed at improving his English reading skills. Recent police reports listed Gonzalez as a Puerto Rican native employed at Old Neighborhood Foods as a machine operator.He is being held in the Essex County House of Corrections in Middleton, charged with child endangerment. Police and the boy’s mother said Gonzalez took his son for a custody visit last Friday.When Daisy Colon came to Gonzalez’ apartment to retrieve their son, the boy was not there and Gonzalez denied having seen him over the weekend. Neighbors told police they saw father and son outside the apartment building Saturday afternoon.Police hauled away a commercial-size Dumpster from in front of 2 Brightwood Terrace Wednesday and searched several parts of the city as the hunt for Giovanni continued.State Police helicopters circled High Rock Park midday and flew over Pine Grove Cemetery. Dirt paths cut through the thick underbrush and trees growing on the park’s slopes. High Rock borders a stretch of Essex Street three blocks from Brightwood Terrace.Searchers also probed earlier in the day around the heights of St. Mary’s Cemetery.By early evening, police had mobilized a grid search in the downtown area.Lynn police Lt. William Sharpe said representatives from the Lawrence Police drug unit had volunteered to join the search for Giovanni Wednesday night.Giovanni Gonzalez is described as a Hispanic male, weighs 40 pounds, is about 4-foot-2 and has a slight birthmark on his inner left ankle. He was last seen wearing blue jeans, a red shirt and “Spiderman” sandals. He was also holding a black “Transformers” backpack.