4 dead in shooting spree spanning two counties in upstate New York*

    * Story Highlights
    * NEW: Frank Garcia went door-to-door in search of victims'
residence, police say
    * Christopher Glatz, 45, wife, Kim, 38, were shot "execution-style"
in their home
    * The couple's teenage children were in the home but were not injured
    * Mary Sillman, 23, Randall Norman, 41, were shot at a hospital
earlier Saturday

(CNN) -- A former hospital worker systematically shot four people in
upstate New York on Saturday, authorities in two counties said.

Frank Garcia, 34, was arrested Saturday afternoon. Garcia knew all four
victims, police said, but they didn't reveal details about the
relationships.

"The individuals who were shot were known to the suspect. It was not
necessarily a random act," Monroe County Sheriff Patrick O'Flynn said.

The first two victims -- Mary Sillman, 23, and Randall Norman, 41 --
were shot before 5 a.m. at Lakeside Hospital in Brockport, where Garcia
was once employed, O'Flynn said. Another woman was wounded and is being
treated at a nearby hospital, he said.

The second shooting happened at a house in neighboring Ontario County in
the afternoon.

Christopher Glatz, 45, and his wife, Kim, 38, were killed
"execution-style" while their two teenagers were in the suburban
Rochester home, Ontario County Sheriff Philip Povero said.

The teens were not wounded but it is unclear whether they witnessed the
event.

Povero said neighbors reported Garcia went door-to-door looking for the
Glatzes' home, but the sheriff not elaborate on any connection among them.

"He was in fact looking for the residence," Povero said. "He was saying
different things to different people, but he was clearly looking for
that home."

Ballistic evidence has connected the two crime scenes, Povero said.
Investigators found the matching brass cartridges from a pistol found on
Garcia when he was arrested, he said.

Garcia was arrested at a restaurant Saturday afternoon, CNN affiliate
R-News in Rochester reported.

Garcia was to be arraigned Saturday night in Monroe County, where the
first shootings occurred, on two counts of first-degree murder and one
count of attempted murder in the second degree, O'Flynn said.

Sillman was a certified nursing assistant at Lakeside's long-term care
center, hospital officials said.

"During Mary's brief time within the system, those who worked closest
with Mary described her as warm, kind and compassionate towards the
residents of Lakeside Beikirch Care Center," Lakeside interim CEO
Michael Stapleton said in a statement.

Garcia likely will face similar charges in Ontario County, Povero said.