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

Card from "Julia L." expressing solidarity with the community.

Folded card with handwritten messages on white paper. The front cover reads: "Love," written in colorful bubble letters. The inside reads: "Your brothers and sisters in Aspinwall love you very much."

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

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: "There can't be light without the dark. We are praying for your safety and peace. Holy Angels CCD." Spelling errors corrected for clarity.

Card from the Friendship Circle of Illinois. The card reads: "To the Jewish community of Pittsburgh sheyichyu (may they live), I will daven for you and give extra tzadakah (charity) and nothing else should happen like what just happened and when moshiach (the Messiah) comes [?] and Hashem will do t'chiyat hameitim (resurrect the dead). The rest of your life should be successful. From so and so... which." The acronym "BS"D" (with the help of heaven), a common header in traditional Jewish letter-writing, appears in the upper left corner.

Post-it note with handwritten message in blue marker. The message reads: "May their memories be a blessing." Signed in Hebrew: [heart] "Miriam."

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.

Handwritten note written in blue ink on a lined notecard reading: "Sending all of my sympathy, empathy and love. I don't know what else to say. -Hope [last name redacted]. Brooklyn, New York (Former Pittsburgher)."

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 blessings and affirmations of love. The church's contact information is included on the back of the envelope.

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 the Friendship Circle of Illinois. The front cover of the card reads: "To the Jewish community of Pittsburgh sheyichyu (may they live)." The card reads: "I feel so bad for you from now and there should be no more bad stuff and moshiach (the Messiah) should come right now!" The acronym "B"SD" (with the help of heaven) appears on the upper right corner of the left fold. There are two illustrations of large smiley faces wearing t-shirts with smiley faces and yarmulkes (skullcaps) with the Hebrew word moshiach (the Messiah).

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The letter reads: "Dear Tree of Life Synagogue, 'Blessed are those who mourn for they will be comforted.' Know God's arms are wrapped around your community and the love of all of us are cradling you. Love, Susan [last name redacted], Moderator, Presbytery of San Diego.

Handwritten note written in black ink on light yellow paper. The note reads: "Dear God, Let love prevail... Let hate fail... Blessed those affected by this terrible act... A Pittsburgher."

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.

Floral tag from floral arrangement sent by Michelle. The tag reads: "Shalom! Love, Michelle." The message is written in black marker on a printed tag with a green background and floral motifs.

Card addressed to Melvin Wax, written using personal details from various public sources.