diff --git a/dist/lib/generalUtils.js b/dist/lib/generalUtils.js
index 64ce8f2a468dd2e309e585db9af80aab06ddca22..6a357588f5975f2f5dabc1e7d116dc1fee3726b0 100644
--- a/dist/lib/generalUtils.js
+++ b/dist/lib/generalUtils.js
@@ -7,7 +7,8 @@ const checkForSubFilter = (pdfBuffer) => {
     const matches = pdfBuffer.toString().match(/\/SubFilter\s*\/([\w.]*)/);
     const subFilter = Array.isArray(matches) && matches[1];
     if (!subFilter) {
-        throw new errors_1.AppError("Can not find subfilter");
+        //SubFilter is only available if there is a sig in the pdf
+        return;
     }
     const supportedTypes = [
         "adbe.pkcs7.detached",
diff --git a/dist/lib/index.js b/dist/lib/index.js
index 6b0086a30113edba2177414a8757b468280c450d..7ed62642f5eb6075926e9f466dead8a95aa30553 100644
--- a/dist/lib/index.js
+++ b/dist/lib/index.js
@@ -10,8 +10,7 @@ const verifyPDF = (pdf) => {
         (0, generalUtils_1.checkForSubFilter)(pdfBuffer);
     }
     catch (error) {
-        //SubFilter is only available if there is a sig in the pdf
-        return null;
+        throw new Error(error.message);
     }
     try {
         const { signatureStr, signedData, signatureMeta } = (0, signatureUtils_1.extractSignature)(pdfBuffer);
diff --git a/src/lib/generalUtils.ts b/src/lib/generalUtils.ts
index 48509ab7fd383b357a5398891a97e5af6acc82f8..6ba8aa23f865fe580f4187c62b7b3dd57bbe8052 100644
--- a/src/lib/generalUtils.ts
+++ b/src/lib/generalUtils.ts
@@ -7,7 +7,8 @@ export const checkForSubFilter = (pdfBuffer: Buffer) => {
   const subFilter = Array.isArray(matches) && matches[1];
 
   if (!subFilter) {
-    throw new AppError("Can not find subfilter");
+    //SubFilter is only available if there is a sig in the pdf
+    return;
   }
 
   const supportedTypes = [
diff --git a/src/lib/index.ts b/src/lib/index.ts
index f603cfdb331b800817364fb9da4a0939cdcd0d3d..81156ab550000e47034e5eece5da39106d147411 100644
--- a/src/lib/index.ts
+++ b/src/lib/index.ts
@@ -7,8 +7,7 @@ export const verifyPDF = (pdf: Buffer) => {
   try {
     checkForSubFilter(pdfBuffer);
   } catch (error) {
-    //SubFilter is only available if there is a sig in the pdf
-    return null;
+    throw new Error(error.message);
   }
 
   try {