Oak Park police are involved in an intense investigation into the brutal murder June 22 of South Oak Park resident Peter D’Agostino. Following four days of canvassing that included much of the southeast section of the village, Oak Park Police Chief Rick Tanksley announced Monday that his department is seeking to locate a “person of interest” in relation to the killing of the 42-year-old D’Agostino. The popular associate professor of history and Catholic Studies, who had both published a well-received book and become a father last year, was apparently attacked while walking home from the Austin Boulevard Blue Line station around 5:30 p.m.

Police and emergency medical responders were first alerted by a 911 cell phone call at 5:32 p.m. from a man who lives across the street from the murder scene. They found D’Agostino lying in the grass near the north end of the 1150 block of South Harvey, unconscious and bleeding from a head wound so severe that initial reports stated he had been shot.

D’Agostino was transported to Loyola University, where he was pronounced dead at 6:01 p.m. The Cook County Medical Examiner later determined that D’Agostino had died from “blunt force trauma” to the head. According to police, he also had a bruise on his right arm, though they say it’s unclear whether or not the bruise was a defensive injury.

Police have no motive at present for the particularly brutal slaying, and they didn’t want to speculate.

“Nothing was taken [that we know of],” said Tanksley. “His briefcase was there, and he still had some personal property.”

Tanksley also dismissed speculation that D’Agostino had been attacked elsewhere and dumped in the 1150 block of Harvey, saying, “We’ve ruled that out,” he said. Tanksley also said that his investigators doubted there was a connection between a reported car door slamming and any assault.

“We’re not sure the car door slam was related to the homicide,” he said, “because the individual we’re looking for did not park in front of the homicide [site].”

Tanksley said that every available resource is being used in the investigation. Officers canvassed the southeast Oak Park neighborhood the evening of the murder, then re-canvassed the next day in an area bounded by Austin Boulevard, Ridgeland Avenue, Garfield Street and Roosevelt Road. That effort included roadblocks at the Austin Boulevard and Lombard Avenue Blue Line stops, during which police passed out photos of D’Agostino and questioned both motorists and commuters. The effort continued over the weekend, and apparently paid dividends.

“This past weekend we identified a witness who observed an individual we’re now looking for,” said Tanksley. “It was through this witness we were able to develop [a] composite [sketch].”

Monday afternoon police began circulating the composite sketch as part of a Community Alert bulletin that included a description of an African-American male estimated to be in his mid-20s to mid-30s, 5-foot-10 to six-foot-two in height, thin to medium build, with a medium complexion.

“This individual, according to witnesses, can be placed on the block of the homicide around the time of the homicide,” said Tanksley. The man police are seeking, he said, was seen by a witness walking down the street to where the incident occurred, then “returning quickly to his vehicle.”

Just as importantly, Tanksley said, police have a description of what they say is a distinctive automobile. The car, a mid-sized older model passenger vehicle, is turquoise or light blue in color, with a maroon or dark-colored front passenger side fender.

Oak Park police stressed that the individual in the widely distributed composite is not a suspect, but is being sought solely as a “person of interest” whom they wish to question. Tanksley urged anyone having any information regarding the person or vehicle being sought to call the Oak Park police station at the main number, 708/386-3800, which will be manned 24 hours a day.

“Someone knows this individual, and someone can provide us information about this unique-looking vehicle, and that’s what we’re hoping for,” he said.

That, Tanksley said, is why he felt it so important to get out the details of what police are seeking, to, as he phrased it, “have everybody’s eyes looking for this individual and this vehicle.”

That get-out-the-word effort included the Oak Park force’s newest members nine police recruits who reported for their first official day of duty Monday. Fresh out of the training academy, they spent their first day on the job not in the usual orientation sessions, but rather walking door to door passing out flyers. Tanksley said Monday that 20,000 additional fliers would be printed and distributed throughout the entire village, including to commuters exiting both the Austin and Lombard el stops.

Monday afternoon a young patrol officer was seen walking the street in the 500 block of Highland, delivering flyers to homes.

“They’re going door to door,” said Tanksley, “putting the flyer in everybody’s box.”

In addition, Tanksley said that officers from his department have sent copies of the composite to all media outlets, and are hand-delivering copies to all Chicago police district headquarters.