Post-it note with handwritten message in green marker. The message reads: "To never be silent at the arms of our oppressors."

Card from a congregant at the Holy Angels Parish. The front cover contains a stock illustration of a haloed dove flying in front of Noah's ark. The inside reads: "Sorry for what happen on Saturday. I prayed for you. Love, Holy Angels CCD." Color bleeding due to water exposure at the memorial site.

Card addressed to David Rosenthal, written using personal details from various public sources.

Post-it note with handwritten message in blue marker. The message reads: "Thank you, so many people who come to bear witness. You meant a lot to us." Signed with a heart.

Printed note in black ink on bright green paper. The note reads: "Hate has no home here. Our hearts are heavy with grief." Tape marks visible on the right and left sides of the note. Color bleeding due to exposure to the elements at the Wilkins memorial.

Post-it note with handwritten message in red marker. The message reads: "Love Wins. Love and prayers from York, AA. T.B.I."

Hallmark card from a member of St. Peter's Episcopal Church in Londonderry, New Hampshire. The front cover reads: "Faith is the friend that comes along when things just seem to go all wrong." The inside reads: "You are not alone in this tragedy. We will pray for God's peace for your community. Love is stronger than hate. Colleen and Michael."

Handwritten card from a student at Goddard Middle School in Littleton, Co. The front cover features the following quote attributed to C.S. Lewis: "Hardships often prepare ordinary people for an extraordinary destiny. C.S.

Post-it note with handwritten message in green marker. The message reads: "Hate is not welcome anywhere."

Card from a congregant at the Holy Angels Parish. The front cover contains a stock illustration of seven children holding hands around a table with a large goblet and loaf of braided bread, and seven doves. The illustration is labeled: "We are people of God's peace." The inside reads: "We are praying for you." The card has been embellished with multi-colored horizontal lines.

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The letter reads: "Dear Tree of Life Synagogue, Though I feel helpless and unsure of what to do or how to help, this I offer. I stand with you, I mourn with you, I fall on my [?] and cry with you, I get back up with you, I move forward with you. Good and beautiful people of Tree of Life. God bless you, Steve."

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.

Handwritten letter written in black ink on lined notebook paper from Jennifer of Indiana, Pa.

Card with colored pencil and marker illustration. When opened, front side shows illustrations of two five pointed stars and a stack of hearts, and is inscribed: "Margow. We are sorry for your loss." Back shows a tree with spiral-shaped branches and heart-shaped bow and arrows with a rectangular border with hearts in each corner.

Typed two-page letter addressed to the Tree of Life synagogue, families of victims, and survivors. Dated Sunday Nov. 4, 2018. The letter includes tributes from multiple individuals throughout western and central Pennsylvania, including Allegheny, Beaver, Elk, Washington, and Westmoreland counties.

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.

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.

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 contains message of condolence and a wish for peace, articulated through citations to the Book of Psalms. The church's contact information is included on the back of the envelope.

Folded card with colored-pencil illustrations. Front features illustration of tree shedding leaves. Interior features sun shining over water and the name "Sarah."