POMPEY, N.Y. (WSYR-TV) – The Pompey Community Church had its first Sunday service since tragedy rocked the congregation and much of Central New York last week.

David Siau (39) of Pompey and his 18-month-old daughter, Mackenzie, were shot and killed last Sunday while on a family vacation in Montana.

David’s wife, Christy Siau (40) was also shot while holding the toddler and seriously injured. The couple’s two other children were able to escape.

David’s sister, Christina Siau (30) was also seriously injured. Investigators say the attacker, Derick Amos-Madden (37) of Oklahoma had mental health issues and was in a previous relationship with Christina. Authorities say he attacked her with a knife, but she fought back and killed him.

During Sunday morning service, the family’s congregation lifted up the Siau family in prayer.

Pastor Dan Werthman of Pompey Community Church lead members of the church in a service of lament, focused on supporting and healing with the Siau family.

“This a service where we come before God and we join with the Siau family, lamenting with them, lamenting for them. A cry is heard in Pompey. We weep for this family, refusing to be comforted, for their father and daughter are gone.”

PASTOR DAN WERTHMAN, POMPEY COMMUNITY CHURCH

Emotions of shock, grief, sorrow, confusion and outrage filled the congregation, but John Siau, father and grandfather of David and Mackenzie, called on the church to not harbor anger in a video message.

“The Siau family has had terrible trespasses committed against us, but our goal is to forgive, and God has told us as we forgive those, He will forgive us.”

JOHN SIAU, FATHER & GRANDFATHER

Several members of the church also called out to God, asking Him to lift up the Siau family during open prayer.

One woman tearfully said in the microphone, “we don’t know what to say, but we know how much we love them. We know how much of an impact they’ve made on each and every one of our lives.”

The Pompey Community Church has created a special fund for the Siau family to help with medical bills, travel expenses and to help care for mom, Christy, and her two surviving children.

If you’re interested in learning more about the Siau Family Fund, click here.