Four of Halman's former Mariners teammates -- Mike Carp, Alex Liddi, Matt Mangini and Dan Cortes -- were among the several thousand in attendance along with Bob Engle, the club's vice president of international operations; Wayne Norton, Seattle's coordinator of European scouting; and Peter Van Dalen, an associate scout in the Netherlands.
The Rev. Keith Louis conducted the service in both Dutch and English so that the Mariners' guests could follow along.
Halman, 24, was buried in the Mariners uniform bearing the No. 56 he wore this past season as a rookie. The native of the Netherlands spent his entire career in the Mariners organization after signing as an international free agent in 2004, and played 44 games with the Major League squad over the past two seasons.
Halman's younger brother, 22-year-old Jason, is being held by Dutch police on suspicion of murder or manslaughter after an early-morning incident on Nov. 21 in the apartment building where the two lived.
Halman was the Mariners' Minor League Player of the Year in 2009 and regarded as a promising outfield prospect with a unique blend of power and speed. He was on the 40-man roster and would have been competing for a role on the club this coming Spring Training.
"Every other thing is secondary when you realize you're not going to see him anymore, and his family is dealing with such tragedy," general manager Jack Zduriencik said. "We're all brokenhearted. I don't know what else to say. We're all grieving. You could sit here and say a lot of things and never say enough. None of us have words for this."
Two weeks prior to his death, Halman had taken part in a series of youth clinics in his homeland as part of the European Baseball Tour alongside fellow Major Leaguers Prince Fielder and Adam Jones.
Louise Molendijk, whose 10-year-old son Matsu spent about 30 minutes receiving personal instruction from Halman in a clinic in Utrecht, Netherlands, didn't know how to break the news to the youngster after hearing of Halman's death on the radio.
"Since Utrecht, all we'd heard was 'Gregory said this' and 'Gregory told me that' and 'Hey, Mum, do you know what Halman told me?'" Molendijk said from her home in Ooltgensplaat. "Matsu even wore a huge necklace for two days because Greg showed the kids his necklace and they were really impressed with it.
"But we had to tell him the news because I did not want him to hear it through the media. The moment I told him that Greg was dead, he was so angry [at Jason], and then the tears came and he cried like a little boy in my arms, and I cried with him."
Molendijk said that word in the Dutch baseball community is that Jason Halman was suffering from "mental confusion" and had been hearing voices, a theory that has not yet been made public by the Dutch police. But those who have been touched by Halman are looking for answers, and so Molendijk passed that along to her son.
"We tried to make him understand that the whole story is so dramatic for the family, because they have lost not only Greg, but also Jason," she said.
Baseball isn't a major sport in Holland, where soccer, skating and swimming are the primary activities. But baseball has a growing following, and young Matsu Molendijk was thrilled to get to know Halman at the clinics, as meeting a Major Leaguer in the Netherlands is a "one in a million opportunity," according to his mother.
And Halman, she said, made those moments remarkable for the kids with whom he worked not far from his hometown, Haarlem.
"He was such a young, enthusiastic, charismatic man. He had that light in his eyes, that magic look," Molendijk said. "He took his time to tell about his youth, his trainings, the stadium in Seattle and that he went to school in the United States. He encouraged them to train and practice a lot and believe in your dream and then finally live your dream.
"All the other players that day were also great, but Greg had that special thing. He made jokes with them, but also was serious. And most of all, I think he was open and reachable. In the half-hour Matsu met him, Greg made an impression for life."