Post-it note with handwritten message in blue marker. The note is written in Hebrew and English. Translated into English, the message reads: "May God protect you when you leave and when you come. Happy Chanukah!" Signed in English by the Abrin family, followed by a heart.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of the words: "Keep Going" and arrows, stars, and other floral motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Letter from Rev. Drew Shofner, the lead pastor at The Church at Severn Run in Severn, Maryland. Addressed: "TREE OF LIFE."

Post-it note with handwritten message in blue marker. The message reads: "I pray to you and remember you always. May your soul rest in peace." Tape affixed on the upper center.

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside reads: "Stay strong, remain faithful, know you're loved. - Scott." The church's contact information is included on the back of the envelope.

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of a turtle with floral motifs on its shell, feet, and neck. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Post-it note with handwritten message in blue marker. The message reads: "May you all rest in eternal peace. God Bless [heart]."

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of a pineapple with floral and geometric motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of the words: "Keep Going" surrounded by stars, arrows, and other floral motifs. The back contains a handwritten note, featuring a quote from the British historian, Richard Evans, as well as the stock signature: "From your friends at West Allegheny Middle School."

Handwritten note written in black marker on dotted graph paper. The note reads: "Pray for the dead and fight like hell for the living." Creasing and staining due to exposure to the elements at the Wilkins memorial.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The letter is dated 11/4/18 and reads: "Dear Tree of Life Synagogue, Please accept our heartfelt condolences in the loss of your beloved congregation members, from our congregation at Point Loma Community Presbyterian Church in San Diego, CA. In LA, I grew up living next to a Rabbi (Marvin Bornstein) and his dear family. He was familiar with loss as well, having left medical school in Vienna at the onset of WW II. I learned from his example of love, tolerance and peace.

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The letter reads: "From Point Loma Community Presbyterian Church, San Diego. Dear members of Tree of Life synagogue, Our hearts ache for your loss and we pray that God will give you peace and hope. We also pray that as a nation and as people of God, we can overcome this senseless hatred. We love you, Judy [last name redacted]."

White envelope with a handwritten note in blue ink, reading: "To Our Jewish Friends and Neighbors." Staining, color bleeding, and minor tearing due to exposure to the elements at the Wilkins memorial.

Folded card with crayon and marker illustration. Cover features smiley face. Interior features illustration of heart and of rising sun. Text reads, "Things do get better. We are so sorry for your loss and all the pain you've endured in recent days. Sending our best wishes and love for healing and peace in the days ahead. Beth [last name redacted for privacy] of Beth Chai Congregation in Maryland.

Folded card with marker and colored pencil inscriptions. Cover reads: "Do not cry :-) That is sad." Inside reads: "I am very sad about the bad things that happened to you. I hope this never happens again. Luke [last name redacted for privacy]" and features stylized illustration of two stick figures, representing the writer "me" and the recipients "you guys" holding hands.

Post-it note with handwritten message in blue ink. The message reads: "I think about you constantly. Sending love." The Hebrew acronym, "with the help of heaven," appears in the upper right.

Post-it note with handwritten message in black marker. The message reads: "I was not here, but I live nearby. Had I been home I could have grabbed my baseball bat, and gone after Bowers."